Excerpts from Books and Wikipedia
"In 1405 the eunuch admiral Zheng He set sail from Nanjing at the head of a fleet of sixty-two ships carrying more than 27,000 sailors and soldiers and a vast amount of treasure. Over the next two years, Zheng He visited Vietnam, Siam (Thailand), Malacca, Java, India, and Ceylon (Sri Lanka). . . . His mission was a flag-flying exercise to show the 'barbarian' kingdoms of Southeast Asia and the Indian Ocean that after a century of Mongol occupation China was a force to be reckoned with. . . . After Zheng's death in 1435, the emperor Zhengtong abruptly ended all maritime enterprises to concentrate his resources on defending China's northern frontier against the resurgent Mongols." [1001 Days] Yet well before those explorers [Dias, da Gama, and Columbus] left their European ports--in the years between 1405 and 1433--Chinese Admiral Zheng He had taken an immense fleet west on seven voyages covering more than 100,000 miles, ranging as far as the Persian Gulf and Kenya. Zheng He's story is all the more remarkable considering that he was a commoner, a Muslim, and a eunuch. . . . A fourth voyage took him to the Persian gulf, where a Chinese mission visited Mecca." [National Geographic Almanac, p. 168-71]