Historical use of penannulars?

[Woodsheal]

The penannular ("almost a circle") brooch is an ancient/medieval item, and does not overlap the period of usage of the belted plaid. None have been dug up at the Culloden battlefield that I'm aware of, including the recent finds there....

Here's a great article on period Highland dress by Mara Riley, who has done extensive research:

http://www.marariley.net/celtic/scotland.htm