A previous castle on the site dating to the 13th Century was the site of the signing of the Treaty of Irvine in 1297. Scottish nobles had gathered at Irvine during the uprising against the English involving William Wallace. An army under the command of Sir Henry Percy and Sir Robert Clifford forced the nobles to surrender and sign the Treaty of Irvine acknowledging Edward as their sovereign.
Most famously it was here in August 1563 that Mary Queen of Scots visited with her 'Four Maries', Mary Beaton, Mary Seaton, Mary Fleming and Mary Livingstone and was entertained by the 3rd Earl of Eglinton. The annual Marymass festival celebrates this visit.