In 1548, Sir William Body, a royal commissioner sent by Edward VI to destroy the Catholic shrines at Helston, was killed by two local Cornish men. In retaliation, 28 local men were arrested and executed at the castle.
Anger grew, and in 1549 a wider uprising called the Prayer Book Rebellion took place. It was headed by Sir Humphrey Arundell, who marched up through the county and took Launceston Castle that summer, probably without a struggle.