Norman Conquest Encyclopedia

The shields of the Anglo-Saxons and the Vikings were, up to the 11th century, round in shape. They were made of wood, covered with cow-hide as a rule and with a metal boss in the centre, the reverse of which was used to create a hand-hold. By the time of the Norman invasion of England, English housecarls were using the same kite shield as their adversaries.

You can find out more about round shields in the following Osprey books:
Warrior 3 Viking Hersir 793-1066 AD page 48 and Plate C
Warrior 5 Anglo-Saxon Thegn 449-1066 AD page 15.

See also: Anglo-Saxon; helmet; housecarl; kite shield; Norman; Viking