The Caliphate at Its Zenith: How Sokoto Looked Around 1850

Half a century after its founding, the Sokoto Caliphate stretched from the Niger Bend to the mountains of Adamawa. Thirty emirates, ten to fifteen million subjects, its own currency system, a flourishing textile industry, a network of madrasas and a rich literature in two languages. It was the largest Islamic empire in Africa after Songhai. And it was, without the sultans in Sokoto fully realizing it, already eroding.

An Empire That Can Be Drawn on the Map

Around 1850, in approximate terms, the caliphate begins in the west at Dendi, in the upper-Niger region, near the city of Say and the western part of what is now Niger, and from there it stretches eastward, across the entire breadth of northern Nigeria as we know it on a modern map. Gwandu guards the western flank, while Kebbi, Yauri and Nupe lie on the southern bank of the Niger and Ilorin, a Yoruba-Fulani emirate, extends the caliphate further south to the edge of Yoruba country near Ibadan. In the center lie the classical Hausa states that under the jihad had been reduced to emirates, Kano, Katsina, Zaria (Zazzau), Daura, and the new Sokoto itself, while to the east lie Bauchi, Hadejia, Gombe and, as the most distant emirate, Adamawa, which extends into what is today Cameroon and the western shore of Lake Chad.

The polygon we display on our interactive map as Sokoto ~1870 captures this area in one closed line, but the actual borders were of course not so neat. Emirates had core areas, the capital and surrounding villages, and peripheral areas where their authority extended in diminishing degrees, and beyond the periphery lay twilight zones where Sokoto commanders occasionally raided but exercised no permanent rule: parts of the Jos Plateau, the Mambila Highlands, the Mandara Mountains, parts of southern Borgu. These twilight zones were fiscally valuable, since slaves came from there, but politically loose.

The area of the caliphate at its peak is estimated by various modern historians at around 500,000 to 800,000 square kilometers, roughly the area of Germany and Poland combined, or ten to sixteen times the Netherlands. Within that space lived, according to estimates by Murray Last, Paul Lovejoy and Sean Stilwell, between ten and fifteen million people, which makes it, in absolute terms, the largest African political entity since Songhai under Askia al-Hajj Muhammad.

The Administrative Pyramid: Caliph, Emirs, Hakims, Maigaris

How was this enormous area governed? Without a centralized bureaucracy of the kind the Chinese or the Ottomans operated, and without a permanent standing army like that of the Mamluks, since the Sokoto Caliphate was, in its essence, a federation of emirates under the theological-political authority of a caliph.

At the top sat the Amir al-Muʾminin, the caliph, based in Sokoto, the ceremonial and spiritual central authority. He received the bayʿa, the oath of allegiance, from every new emir who took office, and he gave the tuta, the formal flag, that legitimized the emirate within the caliphate. He arbitrated in disputes between emirs, he received annual hadiyya, gifts that in practice constituted a form of tribute taxation, and he waged symbolic war, leading personally, or via a commander, campaigns against frontier opponents to keep the jihad alive.

But the direct administration of the thirty-odd emirates, where some counts give 28 and others 30, depending on how some smaller emirates are included, lay with the emirs themselves, and each emir was effectively sovereign within his own territory. He levied his own taxes, appointed his own Qadis, waged his own campaigns against his own enemies, and commanded his own army of cavalry, infantry and, from about 1830 onward, simple firearms acquired through trans-Saharan trade. What he could not do was wage war against another emir without Sokoto’s consent, or pursue a policy demonstrably contrary to the shariʿa as the Qadis of Sokoto interpreted it.

Below the emir lay a second administrative layer, the hakims or sub-emirs, who governed districts within an emirate, and below them the maigaris, the village heads, who maintained daily order in their communities. In Kano alone, the largest emirate, there were estimated to be more than a thousand maigaris, a functioning administrative network that could distribute tax assessments, settle disputes in the first instance, and mobilize military levies.

The Maliki legal system ran parallel to this political system, since every city had a Qadi and large emirates had a Qadi al-Quda, a chief Qadi. Judges were trained in madrasas, through ritual apprenticeship under older fuqaha, and through the study of handbooks like Khalil’s Mukhtasar, the Risala of Ibn Abi Zayd al-Qayrawani ﵀, and the locally produced Diya al-Hukkām of Abdullahi dan Fodio ﵀. Appeal in complex cases went to Sokoto, to the Qadi al-Quda there and ultimately to the caliph himself, so that this was a coherent legal system that integrated legislation, adjudication and appeal within one Islamic legal tradition. For nineteenth-century Africa, this was impressive.

The Capitals: How They Looked

The great cities deserve a brief pause, since a civilization only really lives once its streets can be imagined.

Sokoto itself had around 1850 about twenty thousand inhabitants, not enormous by world standards, since Cairo in the same period was already approaching three hundred thousand and London more than two million, but large by Sahel standards. The city walls enclosed about ten square kilometers, and within the walls lay the Masallacin Shehu, the great Friday mosque, the Gidan Sarki (sultan’s palace), the sabon gari (new quarter) where Arab and North African traders lived, the kasuwar Sokoto (central market), and the library-madrasa complexes. The streets were unpaved but organized in a roughly radial pattern around the mosque, and the houses were of clay, in two or three stories, with the characteristic Hausa sabon peaked roofs on the courtyard model.

Kano was larger, with an estimated thirty thousand inhabitants within the walls and another two thousand in the suburbs and surroundings, and it was the economic center of gravity of the caliphate. Its markets drew traders from Tripoli, Ghat, Agadès, Timbuktu, Kukawa (Bornu), Ashanti country, and even occasionally from British-controlled coastal areas of Sierra Leone and the Gold Coast, while its textile industry, about which more shortly, was the largest employment complex of Hausaland. Its Kurmi market, in the heart of the city, was so famous that nineteenth-century European travelers like Heinrich Barth (1851-1855) wrote pages-long descriptions of it.

Katsina, Zaria, Bauchi, Yola (capital of Adamawa), Ilorin and Gwandu each had between five and fifteen thousand inhabitants, each its own mosque-palace-market triangle, each its own madrasa with trained ulama, and each its own Arabic chancery that maintained correspondence with Sokoto, with other emirates and with North African correspondents. Together they formed a network of urban hubs along which people, books, trade goods and ideas moved.

Kano Indigo: The Textile Industry of Hausaland

One sector deserves extensive attention, because it most strongly shaped the economic character of the caliphate: the Kano textile industry, in particular the indigo dyeing system.

Hausaland grew cotton and indigofera plants, from which the famous indigo blue could be extracted, and it had a guild structure of weavers, spinners, dyers and clothmakers who had passed down their specializations for generations. What made Kano specifically unique were the marinas, the indigo dye pits: deep pits, sometimes up to three meters deep, lined with masonry and filled with a fermenting solution of indigo leaves, potash, urine and water. Cloths were dipped in these pits, oxidized in the air and dipped again, until they reached the characteristic deep-blue to almost-black shibori-like sheen that made Kano clothing famous.

According to Heinrich Barth’s 1851 report, Kano counted between one hundred and one hundred fifty active marina complexes, each with dozens of workers, largely specialized slaves or Hausa guild laborers. The production was processed into stylized rigas and boubous, the great gowns of Hausaland and surrounding regions, and these gowns were traded across the Sahara: Tripoli traders bought them in large quantities, Tuareg chiefs paid in salt, horses or slaves for the finest pieces, and the famous turquerie cultures of Cairo and Istanbul imported batches.

The Kano textile industry was, in its scale, unique in nineteenth-century Africa, and economic historians like Paul Lovejoy and Polly Hill have qualified it as an early proto-industrial production complex, comparable in output to some European regional textile centers of the eighteenth century. It contributed directly to the GNP of the caliphate, generated tax revenue, and drew labor, both free and unfree, from the surrounding rural areas into the city.

The Trans-Saharan Trade: Kola, Salt, Slaves

Kano textiles were one leg of the economy, and the second leg was the trans-Saharan trade, which remained reasonably lively until 1870 despite competition from the Atlantic coastal routes that had by then developed to the south.

What went north? Three great products, of which kola was the first. The kola nut, Cola nitida, was not endemic to Hausaland itself but was imported from Ashanti territory and the Volta region, and Hausa traders bought kola in the forests south of Kano and brought it across the Sahara to Tripoli, Ghadames and Murzuq, where the North African and Mediterranean markets craved it. Kola was the caffeine source of the Muslim world, an almost-required element of social interaction in Maghrebi courts, and a conscious aid for Ramadan, and since one camel could carry between one hundred and two hundred kilos of kola, and a caravan of five hundred camels is described several times in the Tripoli archives in the years around 1850, that is fifty to one hundred tons of kola per caravan, with several caravans going per year.

Second, leather and leatherwork, since the Hausa leatherworking tradition of saddles, shoes, trunks, book bindings and amulet holders was renowned, and “Moroccan leather”, which became famous in Europe as a luxury material, was in many cases actually Hausa leather that came to Europe via Moroccan intermediaries. Third, slaves, of whom we must shortly speak honestly.

What went south? Salt, in the first place, since the Bilma salt from the Kawar oases and the Taoudenni salt from the northern Sahara reached Hausaland in great caravans, and salt was used in Hausaland as currency, for food preservation and for cattle feeding. By 1850, European industrial salt from the Atlantic coastal trade was also beginning to appear in Sokoto markets via southern Yoruba networks, a harbinger of a broader Atlantic connection. Furthermore there came horses from North Africa, Berber horses and Arabian horses indispensable for the emirs’ cavalry, firearms and gunpowder, though in smaller quantities than the coast received, North African glass and ceramics, books and paper, and European industrial textiles that came in via Tripoli.

The economy was, in short, no isolation, but part of a Eurasian trade system that connected via Tripoli, Fez and Tunis with the Mediterranean and via that Mediterranean with Europe, Egypt, the Levant, and ultimately as far as India. Kano gowns were worn in Cairo and Istanbul, and Ottoman coffee was served at Sokoto courts, a global economy in its own pre-industrial form.

Slavery: The Sokoto Reality That May Not Be Glossed Over

Here we must stop and be honest, since no description of the Sokoto Caliphate is complete without a direct confrontation with this reality: the Sokoto Caliphate was a slaveholding society on a scale historically unprecedented for West Africa.

What that means concretely begins with the numbers. The modern historian Paul Lovejoy, in his Transformations in Slavery (third edition 2011), calculates that by 1890, shortly before the British conquest, between two and three million slaves lived in the caliphate, which would amount to ten to fifteen percent up to perhaps a quarter of the total population. This made the Sokoto Caliphate at the end of the nineteenth century, in absolute terms, the largest slave society in Africa, and in relative terms comparable to some Atlantic slave societies such as the American South before 1865.

Second, the origin. Slaves were obtained primarily through raids against non-Muslim populations on the edges of the caliphate: Jos Plateau peoples, Mambila highlanders, Kurfi, Gwari, Mumuye, parts of northern Cameroon and southern Kebbi. The Maliki fiqh framework of Sokoto legitimized these raids as jihad against dar al-harb, provided the opponents were non-Muslim and not under a legitimate peace treaty, while slaves were also brought in by southern Yoruba conflicts and moved through internal buying and selling.

Third, the use. Unlike Atlantic slavery, Sokoto slavery was varied in its labor forms, since a large group worked on plantations around the great cities, the rinji villages around Kano, Sokoto and Zaria, where cassava, millet, cotton and indigo were cultivated, while a second group worked in the textile complex of Kano and a third group in the households of the elite, as servants, concubines, caregivers. A fourth group, often male, often with some education, paradoxically held high administrative or military positions: the royal slaves, who were directly loyal to sultans and emirs and whose status was sometimes higher than that of free Hausa peasants.

Fourth, the Maliki restrictions, since the fiqh set clear limits. Muslims could not be enslaved, though in practice the distinction between “true” Muslim and “syncretistic” Muslim lay in the hands of raid commanders, which led to continuous abuses. Mistreatment was forbidden, manumission, ʿitq, was meritorious and countless wealthy Muslim owners freed slaves in their wills, while children of a slave woman by her free Muslim owner were born free, and the slave-mother (umm walad) received a protected status and was freed upon her master’s death. These were real restrictions that distinguished Sokoto slavery from, for example, plantation slavery in the Caribbean, where such protections were absent.

Fifth, the Atlantic link: some of the Atlantic slaves who eventually ended up in Suriname, on Curaçao, in Trinidad, in America, were originally captured by Sokoto raids and resold via southern routes to the Atlantic traders. The French historian Sylviane Diouf has shown in Servants of Allah (1998) that a significant portion of the Islamic slaves in the American Low Country, some literate in Arabic, names like Omar ibn Said, Bilali Mohammed, Abdul Rahman Ibrahim, came from Hausa, Fulani or Bornu backgrounds. Most Africans carried to the Caribbean came via West and Central African non-Muslim regions, but for a noticeable minority the link with the Sokoto world is direct.

What makes this morally significant is that these were people who fell victim to a twofold slavery: first within an African Islamic empire that considered their unfreedom legally legitimate, then within an Atlantic Christian empire that considered their unfreedom economically necessary. Both forms were terrible, even though they differed in their legal, religious and mortality structures, so that whoever chooses to look at this history only through the European branch misses half the picture, while whoever looks only through the Islamic branch and pretends Sokoto was morally beyond reproach misses the other half.

These are not easy truths, but they belong to this story, and the story is only told properly with eyes that no longer flinch from the complexity.

Taxation, Currency and State Finance

How did Sokoto sustain itself financially? Through a combination of Islamic and pre-Islamic fiscal instruments.

On the Islamic side stood the zakat on grain, on cattle, on trade goods, and the ʿushr, the tenth part of the harvest from ushri land (land on which the state did not levy kharaj), as well as the jizya on non-Muslim minorities within the caliphate, which in Sokoto was rarely applied because the jizya populations lay largely in the periphery where direct authority barely reached. Pre-Islamic or locally adapted were the jangali, a tax on herds, which particularly affected the nomadic Fulani and which functioned both as zakat-like and as land rent, the market taxes, kudin kasuwa, levied at the entrance to the great markets in Kano and other cities, and the tolls on caravans, levied at the borders of emirates.

The caliphate did not use its own minted coins; instead, Maria Theresa thalers (Austro-Hungarian silver coins that from the late eighteenth century onward were popular in North Africa and into West Africa), Moroccan dinars, and for small transactions cowrie shells and salt bars circulated. Salt and cowries were especially favored in the south of the caliphate, thaler and dinar in the north and in international trade, and this multiple currency system worked surprisingly efficiently, though it placed limits on fiscal centralization, so that the state could not pursue monetary policy as the Ottomans or Egypt did.

State expenditures went to maintenance of the court and the chancery, hadiyya to loyal ulama and to regional notables, payment of jund, fighters, after successful campaigns, founding and maintenance of mosques and madrasas, renovations to city walls and palaces, sadaqat to the poor and travelers, and, not to be underestimated, the costly court ceremonies through which the caliphate displayed its legitimacy each year anew on Id al-Fitr and Id al-Adha in a public durbar festival.

Scholarship, Libraries, Female Education

Sokoto was also an intellectual center, since around 1850 Sokoto, Kano, Katsina, Zaria, Gwandu and Ilorin were places where Arabic was taught at a high level, where new books in the Islamic juristic and theological tradition were being written, and where libraries contained hundreds to thousands of manuscripts. The library of the Gidan Sarki in Sokoto, according to Heinrich Barth’s report, contained at least a thousand works, including copies of the Ihya ʿUlum al-Din by al-Ghazali ﵀, the works of al-Suyuti ﵀, Ibn Khaldun’s Muqaddima, all the Maliki classics, and a growing corpus of authors from Sokoto, Gwandu and Kano themselves.

Particularly remarkable was the female educational movement that Nana Asmaʾu ﵀, sister of Muhammad Bello ﵀ and daughter of Usman dan Fodio ﵀, had set up from the 1820s onward and which by 1850 was being continued by her successors. Nana Asmaʾu ﵀ herself, born 1793, died 1864, was tetraglot in Arabic, Fulfulde, Hausa and Tamasheq, a poet of high level with a corpus of more than sixty qasidas, and the architect of the yan-taru system: networks of female teachers who traveled village to village to teach illiterate Hausa and Fulani women Qur’an, basic fiqh, moral conduct and Arabic reading.

Around 1850, her female disciples maintained an active yan-taru network in at least fourteen cities of the caliphate, which is, for nineteenth-century Africa, and for nineteenth-century anywhere, a remarkably large-scale female literacy movement. It is no coincidence that contemporary Nigerian feminists with roots in the north have rediscovered Nana Asmaʾu ﵀ as an intellectual foremother who anchors their own project within the Islamic tradition.

The Comparison with Egypt and Istanbul

To give Sokoto its proper place in the world history of that time, a brief international glance at what other great Islamic states were doing around 1850 is in order.

Ottoman Turkey was in the Tanzimat period (1839-1876), a great ambitious modernization movement in which Sultan Abdülmecid I had introduced centralization, legal equality for non-Muslim citizens, a modern civil code, a centrally collected tax system and a standing army on the European model, while telegraphs, steamships and railways were under development: a Muslim empire actively industrializing and legally modernizing. Egypt under Muhammad Ali, which had de facto detached itself from Ottoman control, had gone even further, with cotton industrialization of the Nile Delta regions, a modern military-industrial complex with arms factories, a standing army formed on French models and educational missions to Paris, so that Egypt in 1850 produced steam engines in its own factories in Cairo.

Sokoto was of an entirely different order: it lacked central tax collection, a standing army, currency production of its own, steam engines and printing presses, and it lacked telegraphs, modern post, modern schools on the European model and consulates in Paris or London; its books were hand-written rather than printed. The caliphate was, in 1850, a pre-modern Islamic state functioning according to seventeenth- and eighteenth-century Maliki blueprints, without the industrial and organizational revolutions that Cairo and Istanbul adopted.

This was not necessarily wrong, since much of the Ottoman and Egyptian modernization project would later lead to great strains, foreign debt and ultimately colonial vulnerability. But it meant that Sokoto, if it came to a confrontation with modern European military power, would do so with horses and spears and a few hundred firearms, against machine guns and telegraphically coordinated armies.

In 1903 that confrontation would come, when British general Frederick Lugard, leader of the Royal West African Frontier Force, would conquer Sokoto in a campaign lasting less than three months and Caliph Muhammad Attahiru I would die in eastward hijra at Burmi. The caliphate that Usman dan Fodio ﵀ had founded, that Bello ﵀ had consolidated, that Abdullahi ﵀ had legally underpinned, that in 1850 had been at its zenith, would cease to exist as an independent state, though the emirate structure would remain, integrated into the British indirect rule system, and survive into the present-day Nigerian republic. But that is 1903, and in 1850 Sokoto is still the great Islamic empire that has redefined the Sahel region.

The Fragility Already Visible

Not everything was rosy in 1850, and honesty about the moment requires naming what was already cracking.

First, succession tensions, since after the death of Bello ﵀ in 1837 there had been six caliphs (Abu Bakr Atiku, Aliyu Babba, Ahmadu Atiku, Aliyu Karami, Ahmadu Rufai, Abubakar Atiku) and every succession had seen tensions. The shura system, by which a small group of notable ulama and emirs selected the new caliph from the descendants of the shehu, was vulnerable to factionalism and to the buying of votes, so that each succession weakened the moral authority of the caliphate a little.

Second, emirate rivalries, since the eastern emirates, Adamawa, Bauchi and Gombe, were growing economically through the expansion of the slave trade and began pursuing their own policies that did not always align with Sokoto preferences, while Kano, as economic gravity, became increasingly independent, and Sokoto remained ceremonial leader but effective coordination diminished. Third, Bornu, since the Sokoto-Bornu conflict of the al-Kanemi-Bello correspondence was never resolved, and Bornu remained, under Umar, the son of al-Kanemi ﵀, independent, so that the eastern border remained a chronic source of tension.

Fourth, external pressure. To the west arose a rival jihad movement under al-Hajj Umar Tal ﵀, who in the 1840s was already receiving bayʿa from Fulanis of Fouta Toro and Fouta Djallon and who by 1860 would found a competing realm contesting Sokoto’s western sphere of influence, while to the northwest, between the Niger and the highlands of Mali, arose the jihad of Seku Ahmadu in Masina, presenting a rival Islamic model to Sokoto, and in the south the European presence grew, with the British in Lagos from 1851, French trading posts on the coast of Dahomey, and steamships on the Niger from 1841. Fifth, the technological gap already noted above, which in 1850 was noticeable but not yet decisive, and which by 1880 would be unbridgeable.

All of this Sokoto did not see, or rather, Sokoto saw it but did not have the institutional means to adapt. The caliphate was optimized for pre-industrial Sahel politics, and when the world outside the Sahel changed, it could not change quickly along with it. That is the tragedy of many pre-modern non-European states: it is not that they were incompetent, but that their competence model was based on circumstances that were rapidly being made obsolete by external forces.

A Civilization in the Mirror of Its Zenith

To conclude, a moment for what all this means when it is read in 2026.

The descendants of those carried across the Atlantic can seldom trace their African roots precisely, and those people were not necessarily from Sokoto itself, since larger numbers came from Yoruba country, Igbo country and the Congo basin; but some were, and for the entire West African complex the Sokoto Caliphate in the nineteenth century was a dominant geopolitical fact.

What Sokoto shows is a picture of what West African Islam at full strength did: learned libraries, juristic traditions, poetic culture, administrative organization, female educational programs, international trade. It also shows what West African Islam did not solve: slavery, tribal hierarchies, inter-Islamic conflicts, the technological complacency that made it vulnerable to the European conqueror.

Both belong to the same history, and neither may be swept under the rug. Thinkers from Marcus Garvey to Cheikh Anta Diop have wrestled with this dual heritage, and this account does so as well, with somewhat more detail than most readers have ever received. Sokoto was great and Sokoto was vulnerable, in parts and at the same time.

Hamdullahi and the Tijani Jihad

The Sokoto complex is now complete in three parts: Bello ﵀ as consolidator, Abdullahi ﵀ as critic-from-within, the zenith around 1850 as snapshot. But Sokoto was not the only great Islamic political formation in nineteenth-century West Africa, since while the Fodio family controlled Hausaland, two other projects developed in the west and northwest, each deserving its own chapter.

In the inner delta of the Niger, around Djenné and Mopti, Seku Ahmadu Lobbo ﵀ in 1818 founded the Islamic empire of Hamdullahi (Masina), a stricter Fulbe reform state that wrestled with Timbuktu and that by 1840 had grown into the great Niger power. And in the west of what is today Mali, Senegal and Guinea, al-Hajj Umar Tal ﵀ from the 1850s onward built a jihad empire that would clash with both Sokoto and Masina and that fixed the rise of the more southerly Tijani tariqa as the dominant sufi order in West Africa.

Hamdullahi and the Tijani jihad are the other half of the nineteenth-century West African Islamic story, and they help explain why the Sokoto Caliphate, however large, never represented the whole of West Africa.

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Sources

• Heinrich Barth, Travels and Discoveries in North and Central Africa (London 1857–1858), the account of the journey of 1851–1855 on which the descriptions of Kano, Zaria and Sokoto rest: the tribute of Zaria to Sokoto in March 1853, two million cowries, five hundred gowns and thirty horses, as quoted in Last, p. 105.
• Murray Last, The Sokoto Caliphate, Longmans, Green and Co, London 1967, pp. lxx, 43, 47, 53, 81, 103–106, 114, 118, 141, 185, 199.
  • pp. 43, 47: the west of the caliphate, with the Niger valley down to Nupe and Dendi and later Ilorin and Liptako under Gwandu; the Muslims of Masina who declared a caliphate of their own and Shaykh Ahmad ﵀ of Masina who refused to acknowledge Sokoto; the sultans of Bornu who had styled themselves Amir al-muʾminin for four centuries.
  • pp. 53, 141: the flag system, by which leaders from Hausaland received their own regions as emirs with a flag blessed by the Shaykh ﵀; the Amir al-muʾminin who went east after the lost battle at Sokoto in 1903, while most office-holders stayed behind under Lugard’s promise of the free practice of Islam.
  • pp. 81, 114, 118: the succession after Bello ﵀: Abu Bakr Atiku without dispute in 1837, Ahmad ibn Atiku in 1859 after the long reign of ʿAli, with the bid of ʿAli Karami, and the four caliphates of 1866 to 1881.
  • pp. 103–106, 185, 199: taxation: in Sokoto only zakat, with the jangali on the cattle Fulani renamed zakat; kharaj in Kano and Zaria and jizya from protected non-Muslims; the revenue from the emirates as “the well-known, agreed gift”, usually ten million cowries for the caliph and five million for the vizier; the kurdin karofi, the tax on the dye-pits of Kano; the yearly booty in captives, legally one fifth; the treasury under the vizier.
  • p. lxx: salt brought in by the Tuareg and kola nuts from Gonja as the major trade goods of the Sokoto area.
• Mervyn Hiskett, The Sword of Truth: The Life and Times of the Shehu Usuman dan Fodio, Oxford University Press, New York 1973, pp. 140–141.
  • pp. 140–141: the hakims as district governors; Gwandu as the western half with its own subordinate emirates; the emirs, first called nuwwab; their obligations to the caliph: raising levies, yearly tribute from taxes and booty, in effect the profits of slave raiding, upholding orthodoxy and continuing the jihad on the borders; the vizier as the link with the emirates.
• R. A. Adeleye, Power and Diplomacy in Northern Nigeria 1804–1906: The Sokoto Caliphate and Its Enemies, Humanities Press, New York 1971 (Ibadan History Series), pp. 3, 40, 65, 285, 288, 309.
  • pp. 3, 40, 65: the caliphate over an area of about 250,000 square miles; the caliph as the source of all authority and the emirs with great independence within the shariʿa; Gwandu’s western sphere according to Barth, with Arewa, Zaberma, Dendi, Gurma including Liptako and part of Borgu.
  • pp. 285, 288, 309: Lugard in Sokoto on 19 March 1903 and the installation of Attahiru II on 21 March; the sultan who lost authority over the emirates and the appointment of emirs that passed to the British; the fall of Burmi on 27 July 1903, where the caliph Attahiru fell with about ninety men.
• Jean Boyd, The Caliph’s Sister: Nana Asma’u 1793–1865, Teacher, Poet and Islamic Leader, Frank Cass, London 1989, pp. 10, 42–43, 49, 51–52, 103.
  • pp. 42–43, 49, 51–52: Bello ﵀ choosing his sister Nana Asmaʾu ﵀ to lead the women; the jajis, the women leaders with the malfa hat and the red band; the pupils known as yan-taru who came to her from village to village to learn religion, obligations and poetry.
  • pp. 10, 103: the death of Nana Asmaʾu ﵀ in 1865, sixty-two years after the events of 1803.
• Sylviane A. Diouf, Servants of Allah: African Muslims Enslaved in the Americas, 15th anniversary edition, New York University Press, New York 2013, pp. 30, 53, 55, 116.
  • pp. 30, 53, 55, 116: Bello ﵀ and other Muslim rulers who released Muslim prisoners and kept only unbelievers as slaves; the caliphate that lasted a hundred years until the British conquest; Bahia absorbing about eight thousand Africans a year between 1800 and 1830, mostly Hausa and Yoruba; Bilali as a Fulbe from Futa Jallon.
• Omar ibn Said ﵀, A Muslim American Slave: The Life of Omar Ibn Said, ed. and trans. Ala Alryyes, University of Wisconsin Press, Madison 2011, p. 109: the origin of Omar ibn Said ﵀ in Futa Toro and of ʿAbd al-Rahman and Bilali in Futa Jallon, in the essay by Michael A. Gomez.