The Entsuin Temple was built next to Matsushima's main temple, the Zuiganji Temple, in 1647 to house the mausoleum of Date Mitsumune, son of the ruling local feudal lord Date Terumune. The temple was built out of mourning and is Kannon, the Buddhist goddess." Dedicated to Mercy, since Mitsumune died a sudden, premature death at the age of 19.
Far back on the temple grounds is the mausoleum, which houses a statue of the young lord on a white horse, surrounded by his most loyal followers, who committed ritual suicide after his death. The interior of the mausoleum is decorated with gold leaf and ornate paintings, which also contain Western symbols such as spades, hearts, diamonds, cross and the oldest Japanese rose image. These symbols were included in the design because the clan had an interest in Christianity and Western technology.