By the “union of Tudor and Stuart” I don’t mean that of England and Scotland, but rather the marriage that facilitated the eventual consolidation of power in James I in 1603 and the later formation of the concept of “Britain.” All of that was a long time in the making and it stemmed from the union of King James IV of Scotland and England’s Princess Margaret Tudor in 1503.
The alliance came together in the Treaty of Perpetual Peace signed on January 24, 1502 at Richmond Palace. The treaty was the first between the two countries in roughly 170 years and it ended what had become nearly two centuries of warfare – that said, it was England and Scotland, so even that two centuries needs to be put in the context of several more of bloody battles over sovereignty.