The importance of the influence of Islam in Africa is hard to overstate. Its influence spread from the North Africa down to the Zambezi River. Eventually many American slaves who practiced Islam were brought over from Africa. Many were literate.
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From GENERAL HISTORY OF AFRICA III
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"(1) The Mediterranean facade of the continent, from the Isthmus of Suez to the Straight of Gibraltar, and adjacent Atlantic coast had been incorporated as an integral part of the Islamic world. It ceased forever to be part of the Christian world and even served as a starting point for further Muslim expansion in Spain and Sicily on the one hand and in the Sahara and the Sudanic zone of West Africa on the other
(2) In north-eastern Africa it had brought about the weakening of the Christian states of Nubia and Ethiopia, though neither of them was conquered. Whereas Nubia had come more and more under the economic and political control of Muslim Egypt and nomadic Arabs began to penetrate it so it eventually lost its Christian character, Ethiopia had survived as an independent political and cultural unit although it had to accommodate its external relations to the growing Muslim influences surrounding it.
(3) The Sahara and large parts of the Sudan had now to be linked through the trade network to an Islamic economic sphere in which their main exports--gold and slaves--played an increasingly important role. The religion and culture of Islam had penetrated along the trade routes, becoming gradually incorporated into the African ways of life
(4) In East Africa the role of international trade was controlled by the Muslims was similar with the important exception that the Muslim merchants had restricted their activities to coastal settlements and Islamic influence did not penetrate into the interior. But the growing, in Muslim countries and India, for Zimbabwe gold and even seems to have led to some changes in the Zambezi region. Some parts of Madagascar and the Comoro Islands were also made a part of the great Indian Ocean commercial network"
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Other Sources
Islam and Africa webpage
Islam in Africa (Wikipedia)
From Wikipedia, "Islam in the United States"
Muslim Slaves in America
"Many of the
slaves brought to colonial America
from Africa were Muslims.[4][5] By 1800, some 500,000 Africans arrived
in what became the United
States. Historians estimate that between 15
to 30 percent of all enslaved African men, and less than 15 percent of the
enslaved African women, were Muslims. These enslaved Muslims stood out from
their compatriots because of their "resistance, determination and
education".[6]
It is estimated that over 50% of the slaves
imported to North America came from areas
where Islam was followed by at least a minority population. Thus, no less than
200,000 came from regions influenced by Islam. Substantial numbers originated
from Senegambia,
a region with an established community of Muslim inhabitants extending to the 11th century.[48]
Michael A. Gomez speculated that Muslim slaves
may have accounted for "thousands, if not tens of thousands," but
does not offer a precise estimate. He also suggests many non-Muslim slaves were
acquainted with some tenets of Islam, due to Muslim trading and proselytizing
activities.[49] Historical records indicate many
enslaved Muslims conversed in the Arabic language. Some even composed
literature (such as autobiographies) and commentaries on the Quran.[50]
Some newly arrived Muslim slaves assembled for
communal Salah (prayers).
Some were provided a private praying area by their owner. The two best
documented Muslim slaves were Ayuba
Suleiman Diallo and Omar Ibn Said. Suleiman
was brought to America in
1731 and returned to Africa in 1734.[48] Like many Muslim slaves, he often
encountered impediments when attempting to perform religious rituals and was
eventually allotted a private location for prayer by his master.[50]"

Omar Ibn Said (ca.
1770–1864) is among the best documented examples of a practicing-Muslim slave.
He lived on a colonial North Carolina
plantation and wrote many Arabic texts while enslaved. Born in the kingdom of Futa Tooro (modern Senegal), he arrived in America in 1807, one month before the U.S. abolished
importation of slaves. Some of his works include the Lords Prayer, the
Bismillah, this is How You Pray, Quranic phases, the 23rd Psalm, and an
autobiography. In 1857, he produced his last known writing on Surah 110 of the
Quran. In 1819, Omar received an Arabic translation of the Christian Bible from
his master, James Owen. Omar converted to Christianity in 1820, an episode
widely used throughout the South to "prove" the benevolence of slavery.
However, some scholars believe he continued to be a practicing Muslim, based on
dedications to Muhammad written in his Bible.[51][52]"
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