Christian Slavery: Conversion and Race in the Protestant Atlantic World (Early American Studies)

I would suggest you look over the r/AskHistorians wiki, here's a link to the relevant page on racism and slavery. You might also be interested in this particular book from the recommended reading list: Christian Slavery: Conversion and Race in the Protestant Atlantic World by Katharine Gerbner considers the development of race and how an ideology of Protestant Supremacy preceded and set the groundwork for a racial ideology of White Supremacy to form the Atlantic slave system.