The land of Merthen was originally part of the manor of
Winnianton, which was given to
Richard, 1st Earl of Cornwall by his brother,
Henry III, in 1225, who then swapped it with Gervase de Tintagel for
Tintagel Castle. Ralph Reskymer obtained Merthen in the early part of the 15th century, and it became a family seat of the Reskymers. John Leland referred to Merthen as being a ruinous manor house in a fair park and a mid 16th-century chart represents it in a wood and with four towers and named Reskymer. The current manor house is thought to have been built in 1575 by
John Reskymer and his wife Grace, due to their coat of arms over the entrance, although it may originate earlier and the coat of arms be an indication of a remodelling or reduction. The 2-storey porch with the coat of arms is in the north front which has many mullioned windows; the east front is 19th-century. In the early 19th century the house was remodelled again, and the interior was renovated in the 20th century. ==Estate==