I just want to say that Robbie is 100% correct. The kilt did not evolve from the leine. It evolved, rather, from the mantle worn on top of the leine, which has, at various times, been called a plaid, or a brat.

Remember, the first form of the kilt was the feilidh-mhor, aka the "belted plaid." The plaid was a large woolen wrap that was worn as an outer layer over the shoulders, like an oversized shawl. It is this garment that changed, grew larger, and at the end of the sixteenth century began to be worn gathered up into folds and belted at the waist.

Remember, too, that "leine" is simply the Gaelic word for "shirt." The Scots who migrated from Ireland to Scotland wore the leine, it is true. But this just means they wore a shirt! The style of tunic they wore in the fifth and sixth centuries was greatly different from the style worn in the fifteenth and sixteenth centuries. The sixteenth century style of leine, with full sleeves and, yes, sometimes a pleated skirt below the waist, represents only one style of leine. There is a temptation at times to assume this style was the onle one ever worn. The fact of the matter is that, despite certain similarities (pleating of the garment below the waist) the leine and the belted plaid are two different garments, having two different origins, and two different functions.

The liene evolved from a simple tunic, and was essentially a long shirt. The feilidh-mhor evolved from a simple wrap or mantle, and was essentially a long wrap that was belted around the waist. The fact that both are pleated is coincidental.

Aye,
Matt