Herstmonceux Castle was built in 1441 by the owner Sir Robert Fiennes, a descendant of the Monceux family who owned the manor at "Herst", eventually known as Herstmonceux. The castle remained in the Fiennes family until 1708 when it was sold to George Naylor, a lawyer of Lincoln's Inn in London. In 1777 the castle was dismantled leaving only the exterior walls standing and remained a ruin until the early 20th century. Between 1913 and 1933 the caste was restored and in 1946 was sold to the admiralty. From 1957 to 1988 the castle grounds became the home of the Royal Greenwich Observatory before it was relocated to Cambridge. In 1992 the castle became a study centre for the Queen's University in Ontario, Canada.
Although the castle is not open to the public the grounds and gardens are a wonderful place to spend a peaceful, relaxing day.