The short answer is that there was very little continuity, if any at all, between West African Islam and the origins of Moorish Science and the Nation of Islam. I also assume there is a sort of unspoken question here, about whether Islam was transmitted from the ancestors of enslaved people to their descendants in twentieth century. As far as we can tell Islam was not transmitted this way in the United States, Moorish Science and Nation of Islam had other roots.

Enslaved West African Muslims

Some enslaved people brought to the United States were Muslims. One remarkable example of the practice of Islam in the United States is the Bilali document, written in Arabic by an enslaved West African man who lived on Sapelo island off the coast of Georgia. He had it in his possession when he died in 1857. It’s a thirteen page Islamic legal text, and clear evidence that there were not only Muslims in the United States, but even Muslims creating written texts.

But very few religious practices and ideas survived slavery intact. Historian Jon Butler has written about the "African spiritual holocaust," the very thorough destruction of African religious practices while in slavery. There are exceptions, we have accounts of Black families transmitting Muslim practices, I know of two mid-nineteenth century accounts from Georgia of people praying at the correct times and fashions for Sunni Islam, but evidence suggests many Muslims and their descendants embraced Christianity.

Where did Moorish Science Come From?

If Moorish Science was an Islamic movement among African Americans, and it did not draw on the practices of enslaved Muslims, where did it come from? One answer is that Moorish Science drew on orientalist ideas about Islam in American popular culture.

Moorish Science seems to have partially inspired by the emergence of the Shriners. Shriners were (and still are) a civic organization founded in 1872. They were a fraternity of white men from the United States, though not part of any college, and they were connected with the Freemasons. Their gimmick was they dressed up like middle easterners, pretended to be Muslims, and did charity work. This was seen as exotic and exciting in the nineteenth century.

Shriners would wear red fez caps, which were traditional in the Ottoman Empire. They would socialize in what they called “Islamic temples.” They named their meeting spaces things like Al Koran, which was the one in Cleveland, or Damascus Temple, in Rochester, New York. They evenly jokingly took an oath to Allah and Muhammed. By the late nineteenth century there emerged communities of Black Shriners.

These Black Shriners were a huge influence on Noble Drew Ali, who would be inspired by their emphasis on Islam and founded a new organization, the Moorish Science Temple.

We do not know much about who Noble Drew Ali was, even for scholars of American Islam he is shrouded in mystery. Where he was born, even his true name, are all contested. He may have been a man named Timothy Drew, born in North Carolina in 1886 to a Cherokee mother and a Black father.

Another scholar, Jacob S. Dorman, has argued that he was a Black man named Walter Brisker. A stage magician who preformed for circuses, pretending to be a Hindu holy man as part of his act to make him seem to be more exotic. Walter Brisker was said to have suddenly become ill and died in 1913. Dorman thinks he did this to hide, and later changed his name and identity to become Noble Drew Ali.

Around the time of World War I a man shows in the historical record calling himself “Professor Drew” appeared in Newark, New Jersey, advertising himself as a “healer and spiritual teacher.” He claimed to have been taught secrets by adepts from Egypt, and to be able to cure tuberculous and lung cancer with his powers. He also purported to have more knowledge of Jesus’ life than was revealed in the Bible. Drew established a short-lived temple, preaching that Blacks were not supposed to be Christians, but Muslims instead.

Drew shows up in history again in the mid-1920s in Chicago, leading a religious organization called the Moorish Science Temple. Moorish Science borrowed much from the Shriners. It took the use of the Fez as a symbol of authority, it adapted Masonic symbols, hand gestures and terms.

Yet the ideas of Moorish Science were different, for Drew, Islam was not just something to partake in for fun, as the Shriners did. Drew had come to believe that Christianity was harmful to Black Americans, he argued that it had been imposed on them as part of slavery, and that they needed to reclaim their roots. The realities of racism, he said, meant that Christianity needed to be rejected. As a response to racism, Drew began to argue that Black Americans were Moors, from northern Africa, and that Moors should be classified as Asians. Drew went further and began to argue that the religion of all of these Moors and Asians, should be Islam.

Drew however did not seem to know much about Islam as it was practiced in the rest of the world. Though Moorish Science borrowed some of the style of the Shriners, there is no indication Drew ever studied Islam or knew any Muslims very well. As such, the kind of Islam practiced by the Moorish Science temple was very different from traditional forms of Islam.

Lacking a background in Islam Drew had to find a text to base his community on, he would create a text called the Circle Seven Quran. This was not the same as the Quran, the sixth century text that is the holy book of Islam, Drew does not seem to have had much knowledge of the Muslim Quran. Instead the Circle Seven Quran was a bunch of plagiarized texts put in one volume, without attribution.

Many of these works included in the Circle Seven Quran were New Thought texts like the Aquarian Gospel of Jesus Christ, a work written in the late nineteenth century purporting to be a New Testament text. Another portion was a modern text, that pretended to be an ancient Buddhist document.

Where did Nation of Islam Come From?

The origins of Nation of Islam are a bit harder to uncover. They are usually traced to 1931 when a Black man named Elijah Poole met a man named Wallace D. Fard. We don’t know much about Fard, even his racial background is hotly debated. By some accounts he was a Syrian or Turkish peddler. Fard introduced him to Islam, and Elijah came to believe that Fard was in some sense divine, eventually coming to believe that Fard was God.

Fard, dispatched Elijah to spread Islam in Chicago in 1934. Shortly afterwards, Fard disappeared. Elijah, now calling himself Elijah Mohammed, claimed to have been left a special role by his teacher, if Fard was God, then Elijah Muhammed was the messenger of God.

Elijah Mohammed, as the leader of Nation of Islam, would teach beliefs that were not found in traditional Islam. Elijah Mohammed began to teach that white people were devils. According to the Nation of Islam, Islam was a specifically Black religion. Nation of Islam also created it’s own cosmology, a creation story radically different from the ideas of the Quran or other Muslims. Nation of Islam taught that the world was 66 trillion years old, that the first inhabitants of earth were Arabic speaking Black Muslims of the tribe of Shabazz. Earth was a paradise ruled by 24 Enlightened Black Muslim scientists. According to their beliefs 66 hundred years ago, a mad scientist named Yacub created a new race of white people, who were literally a race of devils, out of the original Black race. Nation of Islam understood Muhammed, the prophet of Islam, as a Black man who was tasked with converting the white race. He ultimately failed to do this.

Nation of Islam was obviously influenced by Moorish Science. Many of its early converts came from Moorish Science. Moorish Science had also had linked Islam to Black nationalist ideas, so Nation of Islam inherited this connection.

Conclusion

It's actually somewhat surprising that no obvious connection existed between the founding of these these two movements and African Islam. They were American new religious movements, rather than the products of an inherited African tradition.