Board Thread:Warhammer 40k Video Games/@comment-5607736-20130213164912/@comment-3258762-20131204134429

It does specify that it takes place around the time of the last Aurelian Campaign, which is around 999.M41. Cato Sicarius and Titus are captains at the same time. The developers spoke out about it, stating the Space Marine is set during the same time as DoW but in an alternate universe where Cato obviously do not exist.