Japan had some contact with the Europeans in the 16th century. The Portuguese were the first Europeans to visit Japan. Later, the Spanish and Dutch came to Japan to trade. Also, they brought Christianity. Japan's leaders welcomed them at first, but because Europeans had conquered many places in the world, the Japanese were scared they would conquer Japan too. So the Japanese did not let the Europeans come into Japan anymore, except in a small area in Nagasaki city. Many Christians were killed. Only the Chinese, Korean and Dutch people were allowed to visit Japan, in the end, and they were under careful control of the Japanese government. Japan was opened for visitors again in 1854 by Commodore Matthew Perry, when the Americans wanted to use Japanese ports for American whale boats. Perry brought steamships with guns, which scared the Japanese into making an agreement with him.