A large Buddhist monastery Mii-dera also known Ondzё-ji. It was founded in the second half of VII century at the foot of Mount Hiei, near Lake Biwa. During the heyday of the monastery, there were 850 temples and other buildings. Currently, it is still one of Japan's largest monasteries, within which there are more than 40 temples and other buildings. Historically, Mii-dera is linked to another monastery located on Mount Hiei and - Enryaku-ji Temple, the monks of both monasteries were at war with each other, or against another monastery. In addition, the Mii-dera monks involved in the political games between clans of Succession.

Ondzё-ji was founded by Emperor Tammy memory of the murdered brother .  After two centuries of the church got the name Mii-dera (Temple of the three wells), derived from the mountain springs, which bathed the newly born children .  The name of the monastery gave the monk Entin, a former abbot of Mii-dera in 859-891 years .  In this period the monastery became one of the most influential churches of the country, along with the Todai-ji, Kofuku-ji-ji and Enryaku .  After the death Entin confrontation between the Mii-dera and enryaku-ji, who represented different branches (dzimon and Sammon) Tendai sharpened .  Both monasteries were set up their own army of monks who regularly attacked each other, destroyed and set fire to temples and monastic buildings .  Only in the XI century Mii-dera as a result of clashes burned to the ground four times .  Surprisingly, the two warring armies could join together and act together even against someone .  Thus, in the XI and XII centuries, the monks from Mount Hiei twice attacked the town of Nara and the temple of Kofuku-ji . 

In addition, in the XII century the monks of Mii-dera twice participated in the battles for the throne. And the first time they entered the war on the side of the Minamoto clan against clan Taira, while the second has supported Taira clan against the Minamoto clan.

Up to 1367 on Mount Hiei continued peace and tranquility, while one of the monks of Mii-dera was killed at the entrance to the monastery Kyoto Nandzen-ji. Army monastery popped hiking on Nandzen-ji and the support of "colleagues" from enryaku-ji and Kofuku-ji, twice won the Shogun army which has come to pacify them.

When in 1571 the ruler of Oda Nobunaga destroyed the monastery enryaku-ji, Mii-dera was also hit, and most of the monastic army was destroyed. After some time, the remaining monks were allowed once again to build a monastery on Mount Hiei.

Currently, the Mii-dera kept six statues of Buddha and the treasures of Japanese emperors that show the public once a year or on special occasions.