Shade
Sulis, the style fo shield looks correct from what I've seen before as far as celtic armoury... however.... I think the shields I've seen that size are used by foot soldiers not cavalry. Too that, when were horses introduced to the British Isles?
Oh and here's a nice statue of the Morrigan with a similar shield design.
http://www.dryaddesign.com/catalog/morrigan.htm
Oh and here's a nice statue of the Morrigan with a similar shield design.
http://www.dryaddesign.com/catalog/morrigan.htm