I have received another reply giving some things that are included in the legend of St. Olaf: Olav is supposed to have demanded his men decorate their shields with the cross; (Tore Hund ("Tore the Dog") wears a magical reindeer coat (given to him by Lapp wizards?) that turns blows; and axes are mentioned. So these may have been included to fit the legend.
Typical Norwegian chapel de fer (stalhufvú) of the period. Amongst the surviving examples are:
(1-2-3 late 13th/early14th, 4 early 13th/late 12th, 5 later) Thanks to Ringeck.
Druzhina
14th Century Illustrations of Costume & Soldiers
Edited by Druzhina - 29-Sep-2015 at 10:53