Thread:B214/@comment-3245042-20160325192116/@comment-3435913-20160327003737

Galatine, also called the Sword of the Valiant, was weilded by Sir Gawain, the Nephew of King Arthur. Like Excalibur, the sword was a gift from the lady of the lake, essentially giving it the same holy properties as Excalibur, but was overshadowed by its 'twins' more prominent appearance.

That's all there really is that's confirmable about the sword since it isn't mentioned very often. There are other contemporary interpretations that give a more vivid description, bug it may not be too helpful given that Ishibumi provably has his own idea about Galatine.