The history

The people are real. This is what was written about them.

Nobody who knew Spartacus wrote about him. What survives is a few pages each in Plutarch and Appian, a paragraph in Florus, a line in Orosius, and the summaries of the lost books of Livy. These pages say what those sources say, give both numbers where the sources disagree, and say plainly where nothing is known. Each ends with one paragraph on how the game uses it.