[zeristor]

whilst there were many different slave routes the Atlantic slave trade of 12 million people was larger than the Indian Ocean slave trade of 8 or so million people over a thousand years.

https://en.wikipedia.org/wiki/Indian_Ocean_slave_trade

I hadn’t heard of the Zanj Rebellion of the 9th century in Basra:

https://en.wikipedia.org/wiki/Zanj_Rebellion