Itsukushima Shrine was founded in 593, supposedly by Saeki-no-Kuramoto. However, the current style, with the buildings appearing to float on the water, was first constructed in the late Heian period. Taira-no-Kiyomori, governor of Aki Province (now part of Hiroshima Prefecture), was a frequent worshipper at Itsukushima Shrine, and provided funds for its reconstruction by Saeki-no-Kagehiro. The style of buildings connected by corridors was built in 1168.
Because the entire island is considered to be a deity, erecting a shrine on the land would be seen as harming that deity. Hence the structure was built over the sea. As a result, it forms a cluster of shrine buildings seemingly floating on the sea that cannot be seen anywhere else on Earth, a sight which attracts visitors from around the world.
The shrine was a place of worship since it was founded, but Kiyomori's devout faith and the rise in influence of the Taira clan meant that the shrine became famous throughout the realm. After the Taira clan were overthrown, the shrine went into a period of decline in the Kamakura period (1185-1333). But Mori Motonari's victory in the 1555 Battle of Itsukushima placed the shrine under his command, paving the way for its fortunes to rise again. During the Edo period (1603-1867), the shrine became popular with commoner pilgrims, along with the Ise Grand Shrine and the Shikoku Pilgrimage route.
Itsukushima Shrine was registered as a World Heritage site in 1996. The architectural landscape of the Shinden-zukuri style shrine buildings located above the water, the buildings in harmony with their surrounding environment presenting a Japanese standard of beauty, the fact that the original architectural styles have been preserved to this day, and its significance as a facility for Shinto, Japan's endemic religion, were recognized and led to its registration. The Itsukushima Shrine complex consists of 20 structures, including the Main Hall, Offering Hall, Worship Hall, and so on. Of these, six structures are registered as National Treasures while fourteen more (including the Great Torii Gate, the Five-Storied Pagoda, and the Tahoto Pagoda) are Important Cultural Properties.