The original name of Vasai was Vesalé in Sanskrit. Under the Muslim sovereigns it was renamed to Baxay; the Portuguese christened it Bancaim, and the Marathas called it Bajipura. After it was under British rule, it was named Bassein. Finally, after Indian independence it was renamed as Vasai.
Vasai was the seat of the Portuguese power from 1534 to 1739, after which it fell to the Marathas. The Portuguese under Nuño da Cunha built a massive black basalt fort in addition to churches as they found the site to be an apposite harbour. Vasai boomed with the spice trade and the ship building industry. The salubrious climate and the burgeoning profits saw many wealthy fidalgos — blue blooded Portuguese nobles reside here in lavish villas. It later became the town where the Portuguese aristocracy sent their illegitimate sons rather than exhibit their illegitimate offspring. The floor of St Francis Church is paved with the graves of the Portuguese nobility along with their royal insignia.
The Bassein parish is the largest contributor of priests to the Bombay Archdiocese. The parish has also contributed India's only Catholic saint — St. Gonsalo Garcia.