[BroJoeK]

Some forms of slavery were part of the human condition from the very beginning.
Abolition has come to most countries relatively recently.
Notice on this map that Russia is said to have abolished slavery in 1723, but if that's true, then what was the Gulag Archipelago?
It's said Germany abolished slavery in 1220, but then what were the WWII concentration camps?

[BroJoeK]

It's said that Japan abolished slavery in 1590, but that was small comfort to the WWII Korean "Comfort Women".

Some countries on this map have no date of abolition, might we suppose that's accurate?

[Verginius Rufus]

A lot of doubtful dates on that map. I really doubt that the Germans abolished slavery in 1220 (and of course there were lots of smaller states in "Germany" at that time, all part of the "Holy Roman Empire"). People in Soviet Russia were treated worse than slaves in the camps but they were not technically slaves.

In the early Middle Ages European Christians felt that it was perfectly OK to enslave anyone who was a pagan--the term "slave" comes from the ethnic term Slav because so many pagan Slavs were enslaved. Later in the Middle Ages it was OK to enslave Muslims or people with the wrong version of Christianity--or pagans. That was the justification for enslaving black Africans--the fact that they were not Christians.