Clifford arvede baroniet og titlen som High Sheriff of Westmorland i en alder af syv år efter sin fars død under belejringen af Meaux den 13. marts 1422.[2][3] Han overtog sin fars besiddelser i 1435/6.[2]
Sir Robert Clifford (d. 15. marts 1508), som blev gift med Elizabeth (født Barley), enke efter Sir Ralph Josselyn (d. 25. oktober 1478), to gange Lord Mayor of London og datter af William Barley af Aspenden, Hertfordshire af Elizabeth Darcy. Både Sir Robert Clifford og hans svigerfar, William Barley, var tilhængere af kronprætendenten Perkin Warbeck.[4][7][8]
Cokayne, George Edward (1913). The Complete Peerage, edited by Vicary Gibbs. Vol. III. London: St. Catherine Press.
Gerish, W.B. (januar 1907). "Aspenden Church, Herts". The Antiquary. London: Elliot Stock. XLIII: 18-23. Hentet 13. juni 2013.
Richardson, Douglas (2011). Everingham, Kimball G. (red.). Magna Carta Ancestry: A Study in Colonial and Medieval Families. Vol. I (2nd udgave). Salt Lake City. ISBN1449966373.
Richardson, Douglas (2011). Everingham, Kimball G. (red.). Magna Carta Ancestry: A Study in Colonial and Medieval Families. Vol. III (2nd udgave). Salt Lake City. ISBN144996639X.
Richardson, Douglas (2011). Everingham, Kimball G. (red.). Magna Carta Ancestry: A Study in Colonial and Medieval Families. Vol. IV (2nd udgave). Salt Lake City. ISBN1460992709.