Oura Church was built in 1864, after Japan ended its two-century long Seclusion Policy, whereby access of foreigners to Japan was extremely limited and Christianity was banned. Two French priests constructed the church in memory of 26 martyrs who were killed in the 16th century. The structure, as it is seen today, is the result of an 1879 reconstruction which gave it its more Gothic appearance. It was named a national treasure in 1933, the first western-style building in Japan to be given this honour. It is considered to be the oldest church in Japan.