 
| Type | Valeur | 
|---|---|
| Titre | William de Lancaster I and Charter to St. Peter's Hospital, York | 
| Personnes | 
|---|
|  WILLIAM FitzGilbert de Lancaster Baron of Kendal and Lonsdale | 
| Transactions of the Cumberland & Westmorland Antiquarian & Archaeological Society by Cumberland and Westmorland Antiquarian and Archæological Society, 1866, n.s., vol. 9 (1909) | 
| Another source relating to the parentage of William de Lancaster I |