What's all this medieval nonsense? The ballad was most likely written in the 17th century along with many other similar pieces. Also the Barnards and the Musgraves had many estates all over the country, mostly in northern England and southern Scotland, both wealthy landed gentry. As someone said Musgrave would have been sent out to work his way up in another household as a younger son (not the heir). This patchwork of properties throughout the land (and indeed in other lands) was largely due to arranged marriages between the landed gentry.