Despite initial hostilities, by 1549 the Portuguese were sending annual trade missions to Shangchuan Island. In the early 1550s, Leonel de Sousa—a later Governor of Macau—reestablished a positive image of Portuguese in the eyes of the Chinese and reopened relations with Ming officials. The Portuguese friar Gaspar da Cruz (c. 1520 – 5 February 1570) traveled to Guangzhou in 1556 and wrote the first book on China and the Ming dynasty that was published in Europe (fifteen days after his death); it included information on its geography, provinces, royalty, official class, bureaucracy, shipping, architecture, farming, craftsmanship, merchant affairs, clothing, religious and social customs, music and instruments, writing, education, and justice. In 1557 the Portuguese managed to convince the Ming court to agree on a legal port treaty that would establish Macau as a Portuguese trade colony on the coasts of the South China Sea. The Chinese found the Portuguese settlement useful in expelling hostile Japanese sailors, as well as a useful tool to control other aggressive European powers since the Portuguese repelled Dutch invasions of Macau in 1601, 1607, and 1622. The Dutch had even blockaded Zhangzhou's Moon Harbor in 1623 in order to force local authorities there to allow them to trade, while local Chinese merchants sent urgent petitions to the provincial governor pleading for him to allow the Dutch entry into port. China defeated the Dutch in the Sino–Dutch conflicts in 1622–1624 over the Penghu islands and again defeated the Dutch at the Battle of Liaoluo Bay in 1633. Chinese trade relations with the Dutch began to improve after 1637 and in 1639 the Japanese cut off trade with the Portuguese due to the Shimabara Rebellion, thus impoverishing Macau and leading to its decline as a major port.