Joan was the daughter of Sir John Warren of Poynton (b. 1343 - 1369). His mother was Cicely de Eaton and father was Sir Edward de Warenne or Warren, who founded the Warren family of Poynton. Edward was a knight, and the illegitimate son of John de Warenne, last Earl of Surrey and his mistress, Maud de Nerford. Edward is thought to have been born in 1321, was presumably named after Edward II, and died in the late 1360s.

The Visitation of Norfolk in the Year 1563 records Jane Warren as the wife of William Heydon, with a note that their daughter, Isabel married William de Warren (see link below).

Sources

• http://edwardthesecond.blogspot.com/2007/04/amatory-adventures-of-j...
• http://www.thornber.net/cheshire/htmlfiles/warren.html
• Visitation of Norfolk in the Year 1563, Volume 2, page 174

"In the reign of an , Henry IV (1399-1413). 8. William Heydon, of Robert and Cecily (Oulton) Heydon, married Jane, dau. and heiress of John Warren, of Poynton."

Isabel Heydon was their daughter.