The memorial reads: "IN MEMORY OF SIR WILLIAM OLIPHANT OF ABERDALGIE WHO VALIANTLY DEFENDED THIS CASTLE WITH A GARRISON OF 140 MEN AGAINST THE WHOLE OF THE ENGLISH ARMY UNDER EDWARD THE FIRST IN THE YEAR 1304"

Sir William Oliphant was captured by the English Army in 1296, released and became Constable of Stirling Castle where he resisted the English army, but finally surrendered and was imprisoned again. On his release, he accepted the Governorship of Perth under the English occupation from Edward II. He was subsequently captured by the Scots and sent into exile by Robert the Bruce. He rejoined the Scottish army in 1313, and was given land and titles by King Robert. In 1320, he was one of the signatories of the Declaration of Arbroath.