During the age of discovery Portuguese sailors explored the coasts of Africa and Asia. The sailors later established posts at Goa in 1510, and conquered Malacca in 1511, driving the Sultan to the southern tip of the Malay Peninsula from where he kept making raids on the Portuguese. The Portuguese under Jorge Álvares landed at Lintin Island in the Pearl River Delta of China in 1513 with a hired junk sailing from Portuguese Malacca. They erected a stone marker at Lintin Island claiming it for the King of Portugal, Manuel I. In the same year, the Indian Viceroy Afonso de Albuquerque commissioned Rafael Perestrello — a cousin of Christopher Columbus to sail to China in order to open up trade relations. Rafael traded with the Chinese merchants in Guangzhou in that year and in 1516, but was not allowed to move further.