Rabbinic sources remember Rabban Shimon ben Gamliel II as a youth who escaped the massacre at Betar in 135 CE and later as Nasi at Usha, but no source names where he was born.
What would resolve this A datable document naming his birthplace, independent of the Betar and Usha narratives that establish only his later life.
OpenRabbinics, history of the Mishnaic periodMichael Berenbaum and Fred Skolnik (eds.), Encyclopaedia Judaica, 2nd edition