William de Say was born circa 1106 in England to Geoffrey de Say (-c1112) and died August 1144 Battle of Barnwell Castle of unspecified causes. He married Beatrice de Mandeville (-1197) .
Children
| Name | Birth | Death | Joined with |
| William de Say (-1177) | 1133 England, United Kingdom | 1177 England, United Kingdom | Aufrica nic Uilliam of Scotland (-c1169) |
| Geoffrey de Say (c1135-1214) | 1135 Sawbridge, Bishop's Stortford | 19 May 1214 West Greenwich, England | Alice Maminot |
Siblings
| Name | Birth | Death | Joined with |
| William de Say (-1144) | 1106 England | August 1144 Battle of Barnwell Castle | Beatrice de Mandeville (-1197) |
Residences
Footnotes (including sources)
| ‡ General |