No the original meaning of "Common Good" is related to "Common Law" And that actually originated in Rome between the Republic and Empire periods. Your focus on

No the original meaning of "Common Good" is related to "Common Law" And that actually originated in Rome between the Republic and Empire periods. Your focus on the specific dates have nothing to do with the actual originating use of the saying. It can mean "ordinary" or "plain", but not in the context of "Common Good". I think you are trying to obfuscate the meaning by focusing on the peripherals of the context.