in panoply of ancient kings , in chained rings he armoured him ; his shining shield was scored with runes to ward all wounds and harm from him ; his bow was made of dragon-horn , his arrows shorn of ebony , of silver was his habergeon , his scabbard of chalcedony ; his sword of steel was valiant , of adamant his helmet tall , an eagle-plume upon his crest , upon his breast an emerald .