Commodore Matthew Calbraith Perry, representing the U.S. government, sails into Tokyo Bay, Japan, with a squadron of four vessels. For a time, Japanese officials refused to speak with Perry, but under threat of attack by the superior American ships they accepted letters from President Millard Fillmore, making the United States the first Western nation to establish relations with Japan since it had been declared closed to foreigners two centuries before. Only the Dutch and the Chinese were allowed to continue trade with Japan after 1639, but this trade was restricted and confined to the island of Dejima at Nagasaki. After giving Japan time to consider the establishment of external relations, Commodore Perry returned to Tokyo with nine ships in March 1854. On March 31, he signed the Treaty of Kanagawa with the Japanese government, opening the ports of Shimoda and Hakodate to American trade and permitting the establishment of a U.S. consulate in Japan. In April 1860, the first Japanese diplomats to visit a foreign power in over 200 years reached Washington, D.C., and remained in the U.S. capital for several weeks, discussing expansion of trade with the United States. Treaties with other Western powers followed soon after, contributing to the collapse of the shogunate and ultimately the modernization of Japan.