The Portuguese explorer Vasco da Gama landed in Calicut, in present day Kerala in 1498. This discovery and the establishment of a new sea route to India around the Cape of Good Hope gave an impetus to to the Portuguese who wanted very much to exploit it to their advantage and profit from it. They soon realized that they had to have a permanent trading post established to effectively do so. Repeated attempts to do just that along the malabar coast ( controlled by the Zamorin of Calicut) of India proved difficult and finally they decided to try their luck northwards along the coast.
In 1510 under the command of Alfonso de Albuquerque they laid siege upon Goa, then under Sultan Adil Shah of Bijapur. On February 17th he entered the city of Goa for the first time and met little resistance as the Sultan was engaged with his forces elsewhere. Sultan Adil Shah soon came after him with a vengeance and and on May 23rd 1510 Alfonso de Albuquerque had to flee the city of Goa. Determined to win it for good, Alfonso de Albuquerque made another attempt a few months later with the help of a Hindu Chieftain called Timoja . This time his timing could not have been more than perfect. Sultan Adil Shah had just died and the heir to the throne was the infant Ismail Adil Shah. Ela or the city of Goa was under Rasul Khan, one of his generals. After an initial attack on the Arsenal and a quick and bloody battle, Alfonso de Albuquerque victoriously entered the city of Ela, Goa on St. Catherine's Day, November 25th 1510 .
As revenge for his earlier defeat, he massacred and decimated all of the city's Muslim population over the next three days. He however spared the Hindu population and appointed Timoja as his Thanedar. By 1543, the Portuguese were able to extend their control over Salcette, Mormugao and Bardez, thus ending their first phase of expansion into Goa. The territories of Ilhas, Salcette, Mormugao and Bardez formed part of the Portugal's "Velhas Conquestas" or Old Conquests, and formed only one fifth of the total area of modern Goa. By this time, Goa became the jewel of Portugal's eastern empire.