The Jewel Tower is a 14th-century surviving element of the Palace of Westminster, in London, England. It was built between 1365 and 1366, under the direction of William of Sleaford and Henry de Yevele, to house the personal treasure of King Edward III. The original Tower was a three-storey, crenellated stone building which occupied a secluded part of the Palace and was protected by a moat linked to the River Thames. The ground floor featured elaborate sculpted vaulting, described by historian Jeremy Ashbee as "an architectural masterpiece". The Tower continued to be used for storing the monarch's treasure and personal possessions until 1512, when a fire in the Palace caused King Henry VIII to relocate his court to the nearby Palace of Whitehall.
At the end of the 16th century the House of Lords began to use the Tower to store its parliamentary records, building a house alongside it for the use of the parliamentary clerk, and extensive improvements followed in 1621. The Tower continued as the Lords' records office through the 18th century and several renovations were carried out to improve its fire-proofing and comfort, creating the present appearance of the Tower.