Thank you for that answer, but I was actually curious when the more antique practice regarding the slavery of ethnically European peoples ended. I have read that at the time of Charlemagne, certain roman customs involving slavery were still in force. I have also read that the Norse invaders brought their own laws regarding thralls to the Danelaw. I believe I even remember seeing that slavery was still practiced in England at the time of William I. Is that accurate?

France outlawed slavery in 1848 - and they established the colony of Gabon for liberated slaves, just north of Equatorial Guinea.

England outlawed the slave trade in 1807, but the actual practice of slavery lasted past 1807. The abolition movement began in England during the 1790's, however.

Germany abolished slavery and the slave trade in the same year, 1807, with the Stein-Hardenberg Reforms.

Portugal was one of the latest abolishers of slavery, with the practice lasting well into 1868, when slavery in the Portuguese African colonies was officially ended. Britain and the US entered into discussion with Portugal on the subject to help push the Portuguese towards abolishing slavery.

The award for abolishing slavery latest, however, goes to the Spanish, who officially ended slavery in their Puerto Rico colony in 1873.

Sources:
-"African Americans in the Early Republic," by H. Davidson -"Major Problems in African-American History," by Holt and Barkley Brown