It obviously depends on where and when, but I think you’d have a difficult time finding any past empires that are as genetically diverse as contemporary Canada,

It obviously depends on where and when, but I think you’d have a difficult time finding any past empires that are as genetically diverse as contemporary Canada, USA, etc. Even as wide spread as say, Rome or the Ottoman Empire were, they had little-to-no representation of Chinese, Japanese, South American, Indian, and so on. Germans and Poles are more similar to each other than Indians and Colombians.