James Douglas, 4th Earl of Morton, Regent of Scotland, started building Drochil Castle in 1578, three years before his execution by King James VI.[2] The castle has a round tower, 25 feet (7.6 m) in diameter, attached to each of two diagonally opposite corners.Each tower has two gunloops, preventing enemies from approaching the walls.Morton sold the wool from his Drochil estates to a merchant, John Provand, and his tenants from Linton carted it to Edinburgh.The outer walls consist of whinstone rubble, quarried at Broomlee Hill, dressed with red sandstone.