The Scottish great-kilt or great-plaid is a form of rectangular cloak, or belted cloak. It was a very large, rectangle of cloth, laid upon the ground and pleated, then lifted onto the body and belted with the pleats in place and the end of the material flipped over the shoulder and tied around the arm.
A few important things to note are that Clan tartans are *SO* out of period - so don't do it. Especially don't do it if you don't actually belong to the clan you're impersonating, as the real people of that clan might become annoyed...
Also, there is some controversy about how in-period the belted plaid is. If in doubt, wear a simple, belted cloak, which certainly was in period - see the Earisaid (below) for a description of how to wear one of these.
One of the best online sources for kilts in period is: http://reconstructinghistory.com/scottish/
The women's plaid or Earisaid (pronounced "air-e-sitch" and spelt in a multitude of ways) was a much simpler belted cloak, just a blanket-sized piece of cloth belted around the waist, then pinned at the throat.
The advantage of the Earisaid is its versatility. It can be worn in a few different ways to keep the wearer at different temperatures:
- belted at the waist, pinned at the neck and the loop (around the neck) lifted over the head to form a hood
- belted, pinned and the top corners hanging forward over the shoulders
- belted, pinned and the top corners tucked backwards, under the material lying on the shoulders (to leave the arms free)
- belted at the waist and the material folded down and under and tucked back into the belt to form a sort of skirt
An advantage of most belted cloaks is that where the fabric goes into the belt, a "pouch" is formed that can be used (and often was in period) to carry small personal items (it's a good place to put a purse).
Again, the best online source for the Earisaid is the above link, but here's the specific page, which also has pics of how to wear it.: http://www.reconstructinghistory.com/scottish/arisaid.html
Another link on Scottish women's clothing in gerneal: http://www.medievalscotland.org/clothing/scotwomen.shtml