Polybian reforms?

[Maximus of Phoenicia]

I want to play my romani campaign as historically accurate as possible,and i was wondering,when should i activate(is that the correct term)them?

[Maeran]

The historical changes between the Camillan and Polybian legions wasn't really a reform in the sense that some consul sat down and made these changes to equipment one day (neither were the Marian reforms, but they were more rapid, I think). Instead the legion slowly changed over time. With the Polybian reform, you have to upgrade your MIC to get your new troops, so you can have a creeping reform spread across your young empire if you like. In any case, the changes seem to have taken place between the end of the 1st Punic War (241BC) and the END of the 2nd Punic War (201BC). Loose Roman control of Cisalpine Gaul was achieved in the years between, but lost again. So you can feasibly conquer the required cities in northern Italy without being unhistorical in the years between 240BC and 220BC, but they wouldn't be well under Roman rule for some time to come.