Originally built as a chapel dedicated to Thomas Becket (1180). Only the Early English choir and transept survived the Civil War; in around 1690, the nave and tower were rebuilt and the attractive octagonal dome - a landmark from the sea - was added in 1703. In the chancel aisle is a monument to the notorious Duke of Buckingham, murdered in 1628. The church was elevated to cathedral status in 1927 and extensions subsequently made in 1938-9.