William Wallace was the leader of the Scottish resistance to Edward I of England. During a period of truce, the King's barons summoned the Scots to a Court of Justiciary, held in one of the Barns of Ayr in 1297. Now the site of the Wallace Tower, this building was being used by the English as barracks. Wallace's men arrived first, but 360 Ayrshire barons were hanged one by one as they entered the building. When this was reported to Wallace, he mustered a group of men and returned to the Barns at night, where the English were feasting and celebrating their day's work. In revenge, Wallace and his men sealed the building and set fire to it, killing all the occupants. Ayr Castle was also captured and 5,000 English troops were killed, including the judges who had presided over the Scots' executions.
As the Scots left the scene, Wallace stopped at a nearby vantage point to view the blazing remains of the Barns. He is said to have commented: "The Barns o' Ayr burn weel!" Ever since then, the hill has been known as Barnweil Hill. The memorial tower to Wallace was erected in 1856 and, until recently, was available for public access. (Sources: Information Board at the Wallace Tower
NS3321 : The Site Of The Old Barns Of Ayr and "Ayr Stories", by Dane Love)