Complex sentence: The Earl died soon afterwards in January 1514 in Wigtownshire, where he had gone as justiciar, and his son having been killed at Flodden, the succession fell to Gavin's nephew, Archibald Douglas, 6th Earl of Angus.
Split into simpler sentences: The Earl died soon afterwards in January 1514 in Wigtownshire, where he had gone as justiciar. As his son had been killed at Flodden, the succession fell to Gavin's nephew, Archibald Douglas, 6th Earl of Angus.