Where? regions use different sails.
When? sail design changes alot over the medieval period.
Lateen sails are either a Mediterranean, especially Southern Mediteranean, occurrence or a late one.
This is of course a bit vague but with more info I can help more. If you just want reference to use during the medieval period anytime any place you are OK but depends what you are going for.
There ain't nothin' girlie about a tunic...