There may have been two or three wooden churches in Kökar since the last half of 14th century. During the 16th century a Franciscan monastery was founded on Hamnö island. This place became a spiritual and cultural centre for the entire archipelago.
Today the ruins of monastery share their site with current Kökar's church, which is probably third in this place. It was built between 1769 and 1784 in charge of Antti Piimänen (he died before church was completed). Stones of previous monasteries were used in the construction. In the chapel beside the church are archaeological excavations on Hamnö.
The stone church of Gamla Uppsala, built over the pagan temple, dates from the early 12th century. Due to fire and renovations, the present church is only a remnant of the original cathedral.
Before the arrival of Christianity in Sweden, Gamla Uppsala was the seat of Swedish kings and a ceremonial site known all over northern Europe. The settlement was home to royal palaces, a royal burial ground, and a great pagan temple. The Uppsala temple, which was described in detail by Adam of Bremen in the 1070s, housed wooden statues of the Norse gods Odin, Thor and Freyr. A golden chain hung across its gables and the inside was richly decorated with gold. The temple had priests, who sacrificed to the gods according to the needs of the people.
The first Christian cathedral was probably built in the 11th century, but finished in the 12th century. The stone building may have been preceded by a wooden church and probably by the large pagan temple.