even though people have researched and there is so called Historical fact that the kilt developed in the 16th century it is very hard for me to believe that.
The usage of plaid was used by the ancient Gaelic people as a way to teach math, using the stripes as a way to count, who's to say they didn't wrap themselves up. Also the Word "kilt" means to bunch, fold, or pleat so the Irish might have worn their Kilts differently but its is along the same lines.
There is also evidence that the Nords wore a similar garment.