What do you mean "what's a brat"? It's the German version of haggis isn't it?

Before the development of the Great Kilt, the standard of dress in the Celtic and world included the Brat (a similar garment was worn by the Vikings as well). A Brat is simply a piece of woolen cloth that one would wear over their other clothing. (Brat translates to "cloak" in Gaelic.)

There is some really great historical information available on the Clan Strachan website. Take a look at the link below. (This link will open a PDF file.)

clanstrachan.org/newsletter/A_KTJ_Brief_History_of_Kilts.pdf