Why 272 BC?

[Spartan198]

No Chremonidean League, no wars between Pyrhhus and Rome yet, no Galations tearing up the Maks and others yet, even further away from baktria's official decalration of independence, possibly even no Aedui/Arveni civil war yet. I'm sure there are others.

Ah, okay.
But I'd thought that the Chremonidean League was the Athens / Rhodes / Sparta alliance seemingly portrayed as Koinon Hellenon?

[Korlon]

Ah, okay.
But I'd thought that the Chremonidean League was the Athens / Rhodes / Sparta alliance seemingly portrayed as Koinon Hellenon?

It didn't exist at 280 BCE. I believe I've heard it didn't even exist at 272 BCE, but they were already basically in an alliance, just that the official alliance didn't happen a few years later.