Like their menfolk, the female indigenes of the archipelago, gradually cover their upper torso with short, sleeved collarless blouses called baro, through the 400 years of colonization. And what was, since ancient times, an all-purpose brief wrap-around skirt--metamorphosed into the long skirts called saya. Interestingly the saya was generally fashioned out of opaque plaid or striped cotton and sinamay varieties, while the baro was rather stubbornly made quite persistently of sheer fabrics.
This two-piece ensemble usually supplemented by the ancient tapis used as an overskirt, and eventually by the square kerchief called alam[ay worn so that it covers the bosom--would be the archetypal clothing if the India of the Philippines. The saya was to remain unelaborated until the period of intensified global trade. But to the baro was almost immediately devoted the most laborious artistry, expressed in embroidery and supplementary weft floats. The Spanish presence was echoed in the patterning of the baro: floriate, trellis-like, lace-like designs soon enough make for the standard "look."
Barbie in Baro't Saya
sources: http://www.filipinoheritage.com/costumes/dress3.htm, http://www.manika.com and http://www.barongatsaya.com/s-cart/history.phtml