Sir Reginald FitzUrse (1145 – 1173) was one of the four knights who murdered Thomas Becket in 1170.

His name is derived from Fitz which is a contracted form of the Norman-French fils de, meaning "son of" and Urse from the Latin ursus, meaning a bear, probable nom de guerre of his ancestor. Although he lived before the true age of heraldry which developed in the early 13th century, his shield bore the cognizance of a bear.

http://en.wikipedia.org/wiki/Reginald_Fitzurse

See also MedLands, Reynold FitzUrse.