Where was the castle located in which is related to William Douglas and Margaret Hay?
George Douglas, 4th Earl of Angus:  He was the son of William Douglas, 2nd Earl of Angus and Margaret Hay of Yester. Yester Castle: Yester Castle is a ruined castle, located 1.5 mi south east of the village of Gifford in East Lothian, Scotland.
i don't know