Adam Fitz-Peter de Birkin
Adam Fitz-Peter was born about 1136 in Birkin, Yorkshire, England.  He died before 1185.

 Maud de Caus
Maud was born in 1136 in Shelford, Notthinghamshire, England.  She died at the age of 88 in 1224.

 John de Birkin
John was born about 1166 in Laxton, Northumberland, England.  He died in 1227.