The families with a "Fitz-" prefix go back to some of the supporters and soldiers of William the Conqueror, the first Norman king of England.  William's invasion of 1066 established the unification of England.  The invaders were given land as a prize which was maintained from that period to the present. Beyond that the Fitz prefix is a family name of Normandy, France established by Danish invasions and settlement.  Earliest connections go back to some of the first Danish kings,  Gorm the Old of about 936 was succeeded by his son, Harald Bluetooth. Harald went off each season for raiding and pillaging from Denmark to Normandy.[wikipedia.com]

Some researchers and historians of heraldry have claimed that the name goes back to the Norman invasions of William the Conqueror.  Land was distributed to his followers. One of the earliest names mentioned is Bruning de Cestretona of 1086 in Cornwall.  Robertus filius Bruning is listed in Yorkshire in 1203.  Agnes Browning of Yorkshire is listed in the Yorkshire Poll Tax of 1379. [www.4crests.com]