Portugal and Japan started their first affiliation in 1543, when the Portuguese became the first Europeans to reach Japan by landing in the southern archipelago. They had a significant impact on Japan, even in this initial limited interaction, introducing firearms to Japanese warfare. The American Perry Expedition in 1853–54 more completely ended Japan's seclusion; this contributed to the fall of the shogunate and the return of power to the emperor during the Boshin War in 1868. The new national leadership of the following Meiji period transformed the isolated feudal island country into an empire that closely followed Western models and became a great power. Although democracy developed and modern civilian culture prospered during the Taishō period (1912–26), Japan's powerful military had great autonomy and overruled Japan's civilian leaders in the 1920s and 1930s. The Japanese military invaded Manchuria in 1931, and from 1937 the conflict escalated into a prolonged war with China. Japan's attack on Pearl Harbor in 1941 led to war with the United States and its allies. Japan's forces soon became overextended, but the military held out in spite of Allied air attacks that inflicted severe damage on population centers. Emperor Hirohito announced Japan's surrender on August 15, 1945, following the atomic bombings of Hiroshima and Nagasaki and the Soviet invasion of Manchuria.