All of the information in this essay came from A People's History of the United States, by Howard Zinn, and Lies My Teacher Told Me, by James W. Loewen, both of which uses primary sources such as eyewitness accounts, journal entries, and letters from Christopher Columbus himself.
This issue keeps coming up and, despite my footnotes, I keep seeing commentary about it so I'm going to address it here.
Initially, Bartolomé de las Casas advocated the use of African slaves instead of native labor.
In the first few years after he renounced his land and title, his initial cause was to end the suffering of the natives,
rather than seeking an end to the institution of slavery itself, and so this became his deplorable rationale for the endorsement of African slavery.
Bartolomé de las Casas eventually retracted those views, however, and came to see all forms of slavery as being equally wrong.
In The History of the Indies published in 1527, he wrote the following:
I know that the discovery of the New World means a lot of different things to a lot of different cultures.
I like the sound of Bartolomé Day. If you don't like that, call it Indigenous People's Day.
Or perhaps Chris-Columbus-was-a-turd Day.
I'd even settle for just calling it MONDAY.
But please, oh please
do not call it Columbus Day.