Mistress Jeanne de Valletort Warenne, (not married)

A merged profile had d.o.b. c1168

[Terry Jackson Volunteer Curator 10/04/2015]

The "House of Cornewall" credits her with Walter and Lawrence as well as Richard, plus daughters Isabella and Joan. https://archive.org/stream/houseofcornewall00live#page/30/mode/2up

rom Wikipedia

Richard also had several documented out-of-wedlock children. One of Richard's mistresses was Joan de Vautort, widow of Ralph de Vautort (d.1267), feudal baron of Harberton, Devon and Trematon, Cornwall. Joan later married Sir Alexander Okeston, lord of the manor of Modbury in Devon, which manor, part of the Vautorts' feudal barony of Harberton, had been granted him by Roger de Vautort. Joan bore her second husband a son and heir, Sir James Okeston.

By Joan de Vautort or other mistresses, the Earl of Cornwall had three sons and two daughters as follows:

Philip of Cornwall, a priest. Sir Richard of Cornwall, who received a grant from his half-brother Edmund, 2nd Earl of Cornwall, (d. 1300) in which he was called "brother". He married Joan FitzAlan, daughter of John FitzAlan, 6th Earl of Arundel, and by her had three sons and a daughter. He was slain by an arrow at the Siege of Berwick in 1296. His daughter, Joan of Cornwall, married Sir John Howard, from whom the Howard family, Dukes of Norfolk, are descended. Sir Walter of Cornwall, who received a grant of the royal manor of Brannel, Cornwall, from his half-brother Edmund, 2nd Earl of Cornwall (d. 1300) in which he was called "brother". He was ancestor of the Cornwalls of Branell. Isabel of Cornwall, who received a grant from King Henry III in which she was called "niece". Joan of Cornwall, daughter of Joan de Vautort, in 1283 received a grant from her half-brother Edmund, 2nd Earl of Cornwall (d.1300) in which she was called "sister". The younger Joan married twice, firstly to Richard de Champernowne (2nd son of Sir Henry Champernowne of Clyst Champernowne, Devon), by whom she had a son, Richard de Champernowne, and secondly, Sir Peter de Fishacre, of Combe Fishacre and Coleton Fishacre, Devon, by whom she had no issue. Her childless half-brother Sir James Okeston made her son or grandson Richard de Champernowne his heir.