Although Jorge Álvares was the first to reach the island of Lintin in the Pearl River delta in May 1513, it was Rafael Perestrello, a cousin of Christopher Columbus, who became the first European explorer to disembark on the south coast of China and to trade with Guangzhou in 1516. In 1517, the Portuguese launched a large commercial expedition in Guangzhou and sent a delegation on behalf of Manuel I of Portugal to the court of Emperor Zhengde, relations quickly degraded after death of the emperor when the ambassadors of Malacca (in present-day Malaysia) accused the Portuguese of having dethroned their king.In 1521 and 1522, Chinese naval forces expelled the Portuguese ships and the first rear-loading culverines arrived in China.