the Ottoman empire did not have slavery based on skin color, just conquest. that was through the 1800’s.
Slavery existed in the world long before Europeans came to North America, and continued to exist in the world after the Emancipation Proclamation and ratification of the Thirteenth Amendment to the U.S. Constitution.
It was, is, and will be, a morally abhorrent practice no matter the skin color of the slave or slaveholder.