Her Majesty's Royal Palace and Fortress the Tower of London, less formally known as the Tower of London or simply ‘the Tower’, was the seat of royal power in England for several centuries following its construction by William the Conqueror in 1078. While now a popular tourist attraction, it remains the home of the Crown Jewels, is a working barracks and maintains many ceremonial traditions of state. Two chapels are located within its walls. Foremost of these is the late eleventh-century chapel of St John the Evangelist (St John's), located within the White Tower, noted as a rare surviving example of early Anglo-Norman ecclesiastic architecture. To the north-west, the Chapel of St Peter ad Vincula (St Peter's) has an equally remarkable history and is a building of singular importance even within the Tower complex. Its origins may be traced, like many London parish churches, to a small, private house-church in the ninth century, before being subsumed within the boundaries of the fortress. The chapel, the latest of three documented iterations, was constructed between 1519 and 1520 and is the burial place of many notable figures, including the sixteenth-century queens Anne Boleyn, Catherine Howard and Lady Jane Grey, together with Cardinal John Fisher and the former Lord Chancellor Sir Thomas More, both now venerated as martyrs and saints in the Roman Catholic Church.