I don't know officially but I think GOTA probably takes place in 79 BC. It depends how much time passes in GOTA, I don't think it could be more than a year. It seems likely that S1 started in 74 BC as we know that the S1 finale and all of S2 is set in 73 BC. Though it's possible that the very beginning of the show (with Spartacus fighting for the Romans) happened over a longer period of time. Interestingly we know certain dates in the show due to references to real festivals, for instance 1x03 takes place in August (for the Vulcanalia).

@PenguinSuzie oh thats really interesting about dating through festivals, I didn't know that!

I agree, Vengeance is for sure in 73 BC. Historically (as I understand it), the actual war only began after the two battles at Vesuvius, which occurred within several weeks to a few months after the spring of 73 BC.

I agree with your assessment of GOTA as well, partly because of Lydon being there. He's the only gladiator we know for sure to be from Hispania/Iberia, and the Sertorian Wars in Hispania began in 80 BC and prompted an upswing in captured warriors from there. It's definitely possible that Lydon was captured from before the Sertorian Wars, but I think the timing lines up so well that it's more likely that he was captured during, and hold only been at the ludus a few months to a year. This lines up with the discussion between Glaber and Marcus about Pompey struggling with the Sertorian Wars, which had been going on for several years at that point.

Blood and Sand is hard to date because of the ambiguous timeline of "The Red Serpent", so I agree that Spartacus only comes to the ludus in late 75 or early 74 BC.

Thanks for you input!