 Complete the following phrase:  William Montagu, born at Cassington, Oxfordshire in 1301, was the second but eldest surviving son of William Montagu, 2nd Baron Montagu, and Elizabeth de Montfort, daughter of Sir Peter Montfort of Beaudesert, Warwickshire. by MatildaMaud de la Mare daughter and heiress of Henry de la Mare of Ashtead, Surrey, Royal Justice, Seneschal of William Longspree II Earl of Salisbury. The Montagu family, a West Country family with roots going back to the Conquest, held extensive lands in Somerset, Dorset and Devon. The father, William Montagu, distinguished himself in the 