True. Slavery became common within much of Europe during the Dark Ages and it continued into the Middle Ages. The Byzantine–Ottoman wars (1265–1479) and the Ottoman wars in Europe (14th to 20th centuries) resulted in the capture of large numbers of Christian slaves. The Dutch, French, Spanish, Portuguese, British, ARABS and a number of West African kingdoms played a prominent role in the Atlantic slave trade, especially after 1600.
So from what we know of, the Arab Empire enslaved Christians in 1600.
