Here is one of the more interesting lines of descent tracing Elizabeth Willoughby to William the Conqueror, Duke of Normandy and King of England:
1. Elizabeth Willoughby 1512-1562=Sir Fulke Grevill, knight
2. Edward Willoughby= Margaret Nevill 1495-?
3. Richard Nevill, Lord Latimer abt. 1468-1530=Ann Stafford
4. Sir Henry Nevill d. 1469=Joan Bouchier
5. George Nevill, Lord Latimer abt. 1414-1469=Elizabeth Beachamp
6. Ralph Nevill, Earl of Westmorland=Joan Beaufort abt. 1379-1440
7. John of Gaunt, Duke of Lancaster 1340-1399=Katherine de Roet
8. Edward III, King of England=Philippa of Hainaut 1310-1369
9. William III, Count of Hainaut d. 1337=Jeanne de Valois
10. John II, Count of Hainaut d. 1304=Philippa of Luxembourg
11. John I d'Avenes, Count of Holland=Adelaide of Holland d. abt. 1284
12. Florent IV, Count of Holland=Mechtilde of Brabant
13. Henry I, Duke of Brabant=Matilda of Flanders d. 1210/1211
14. Mathew of Alsace=Mary of Blois 1136-1182
15. Steven of Blois, King of England 1096-1154=Matilda of Bolougne
16. Steven, Count of Blois=Adela of Normandy abt. 1062-1137
18. William the Conqueror, King of England 1027-1087=Matilda of Flanders