Something that came up while researching the covenanters/wars of the three kingdoms in the 17th century (background to the mill at Fyvie, there having been a battle at Fyvie Castle itself and a massacre at Aberdeen) was how many Scottish people were mercenaries in Europe. I wondered how far this might explain Child's finding of ballads in Sweden that were similar to English/Scottish ones. Might this result from the 17th century or are the sources he gives too early in relevant cases?