Joan was a daughter of Richard Neville, 5th Earl of Salisbury and Alice Montagu, Countess of Salisbury. Alice was a daughter of Thomas Montacute, 4th Earl of Salisbury and Eleanor Holland. Eleanor was a daughter of Thomas Holland, 2nd Earl of Kent and Alice FitzAlan. Alice was a daughter of Richard FitzAlan, 10th Earl of Arundel and Eleanor of Lancaster.
(Wikipedia)