Joan Okeston of Cornwall, heiress of Modbury

Joan of Cornwall was the daughter of Richard Plantgenet, Earl of Cornwall and Joan de Valletort. However, she was the legal daughter of Joan de Valletort's husband, Alexander Okeston. Joan of Cornwall was not related by blood to Alexander Okeston.

Joan of Cornwall, (alias Joan Okeston, legally the daughter and heiress of Sir Alexander Okeston of Modbury, Devon)[19] who in 1283 received a grant from her half-brother Edmund, 2nd Earl of Cornwall (d.1300) in which she was called "sister".[20] Modbury was part of the Valletorts' feudal barony of Harberton and was granted to Sir Alexander Okeston, following his marriage to the Earl of Cornwall's mistress, Joan, widow of Ralph de Valletort, by Roger de Valletort, Ralph's brother.[21] She married twice, firstly to Richard de Champernowne (2nd son of Sir Henry Champernowne of Clyst Champernowne, Devon), by whom she had a son, Sir Richard de Champernowne, and secondly, Sir Peter de Fishacre, of Combe Fishacre and Coleton Fishacre, Devon,[22] by whom she had no issue. Following the death of her childless brother Sir James Okeston, the manor of Modbury was conveyed by order of Edward II (1307–27, great-nephew of Richard, Earl of Cornwall), to his sister's grand-son Sir Richard de Champernowne.[23]

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