The story of Gaspar da Gama is a fascinating one. According to his own story, he was born in Posen, Poland in 1444. He became a Jewish traveler, made his way to Jerusalem and then Alexandria, was taken prisoner and sold as a slave in India, where he obtained his freedom and entered the service of the ruler of Goa. There, he took on the name Yusuf 'Adil. We do not know what his original name was.
When the Portuguese explorer Vasco da Gama arrived off Angediva in 1498, he was greeted in a friendly fashion by this long-bearded European on behalf of his master. Vasco da Gama self-righteously seized the Jew and compelled him to embrace Christianity under the baptismal name of Gaspar da Gama. He was also known as Gaspar d'Almeida and Gaspar de las Indias.
As a Catholic, Gaspar da Gama became the pilot of Vasca da Gama's fleet. He successfully guided the ships through treacherous Indian waters and was subsequently brought back to Portugal.
In Lisbon, Gaspar was granted a pension by the king, who employed his linguistic ability in subsequent Portuguese naval expeditions. In 1500 he accompanied Cabral on his voyage in western waters and was with Nicolau Coelho when he first stepped ashore in Brazil.
On the return voyage he met Amerigo Vespucci, the Tuscan explorer after whom America is named, at Cabo Verde and was consulted by him.
In 1502, he went to India once more with Vasco da Gama and again in 1505 with Francisco d'Almeida. He took part in the latter's expedition against Calicut in 1510, when he may have died.
Sources: Gates to Jewish Heritage