Griffin, or Grufudd, is a Welsh name. It means prince or lord. Since this name abruptly enters a Norman family, a good guess is that Griffins mother was a Welsh princess. A welsh royal family is cited in the link in the " about section" discussing land transactions. The dates match his adult lifetime as already given. This makes perfect sense as they are living on land at the Welsh border. I'm still not sure why this document calls him Griffin de la Pole, but a Welsh prince.
Family name and background regarding land, and other family relationships:
http://en.wikipedia.org/wiki/Gruffydd_ap_Gwenwynwyn
Eve Fitz Warin is named as Griffin Warren's mother.
Her parents were Fulke III Fitzwarin and Matilda VaVasour:
Matilda le VAVASOUR [Parents] "Maud" 1, 2, 3, 4, 5, 6, 7, 8, 9 was born 1183 in Edlington, West Riding, Yorkshire, England. She died 1226 in Whittington, Shropshire, England. Maud married 10 Fulke III FITZ WARIN on 1207 in Whittington, Shropshire, England.
http://freepages.genealogy.rootsweb.ancestry.com/~hwbradley/aqwg782...
This page has Griffin as the son of Eve Fitz Warin and Llewelyn the Great.
He also has siblings.
@http://www.geni.com/path/Judy+Rice+is+related+to+Griffin+de+Warren?... is my 21 st uncle this is my lineage Judy Rice
http://freepages.genealogy.rootsweb.ancestry.com/~hwbradley/aqwg782...
This page has Griffin as the son of Eve Fitz Warin and Llewelyn the Great.
He also has siblings.