The Chapel of St Mary's in the grounds of Lulworth Castle is reputed to be one of the finest pieces of architecture in the county of Dorset.
In 1786 Thomas Weld engaged the architect John Tasker to build the Chapel and family tradition tells that King George III gave his permission to "build a mausoleum and you may furnish it inside as you wish". In 1789 the king and queen Charlotte visited the Chapel and gave their approval. In 1790, John Carroll, the first bishop in the United States was consecrated here. The altar, crucifix and candlesticks were made in Rome, to the design of Giacomo Quarenghi.
The impressive organ was made by Richard Seede of Bristol in 1785. Originally built for the Castle it was installed here instead.