Osaka is situated on both banks of the Yodo River and along the eastern shoreline of Osaka bay. Osaka’s old name was Naniwa. According to legend it was founded by Jimu, the first legendary emperor of Japan, who landed in Osaka bay in 660 b.c.e. In 313 c.e., Emperor Nintoku made Osaka his capital.
Various other emperors in subsequent times, such as Kotoku in 645 and Shomu in 724, also resided in Osaka. However, the city of Osaka gained prominence in the 16th century when it became a popular Buddhist religious center.
Toyotomi Hideyoshi built the castle of Osaka on the site of the great Buddhist monastery and made it his headquarters as he dominated Japan in the late 16th century. Osaka also rose to economic prominence as the city, along with Kobe and Yokohama, became the main trading links with Korea and China. Osaka became even more important under the Tokugawa Shogunate and was established as the commercial capital of Japan.
Christianity was first preached in Osaka by Father Gaspar Vilela in 1559. By 1564, five churches were erected in Osaka City and its periphery. Between 1577 and 1579, the number of Christians in Osaka were estimated at between 9,000 and 10,000, which grew to an estimated 25,000 by 1582.