I'm actually "Mrs. Hansio", but you can call me Miss.

In any case, "Braveheart" represents (albeit in a highly fictionalised & completely unreliable way; for instance, the script has William Wallace having an affair with a French princess waaaaaay out of his league a full 6 YEARS after he was executed as a traitor---what a guy! Also, it bears noting that Edward II & Isabella had 4 children, amongst whom was the EXTREMELY manly paragon of chivalric machismo, Edward III, to say nothing of his grandson, Edward the Black Prince---ooooh, baby!) events that occurred in the late 13th & early 14th century.

Sorry, I digress....Buttons were a major development in clothing during the 14th century; they were generally made of the same fabric as the garment (typically wool, as buttons would be for outer garments--both sexes wore a simple linen "shirt" beneath their clothing), that had been twisted or rolled into little ball-like shapes. They were fastened with loops, rather than buttonholes, which didn't come along until a bit later.

Now, it bears keeping in mind that Scotland was basically the back of beyond in 1500, and fashions that were au courant in Italy were about 50 years away from reaching the barren North. That said, by the turn of the 16th century, the Scots were certainly familiar with buttons, although they were NOT yet wearing The Kilt!

Good luck with your project!