Sigtuna was founded to be the first Christian town in Sweden – the center of the new religion. The powerful church ruin, from the early Middle Ages, holds many secrets.

The construction of St. Olaf’s church probably began in the first half of the 12th century. The remains have been the subject of several smaller scientific excavations in the 2000s, when researchers have been curious about the church’s remarkable architecture. The excavations found that the church remnants of today rest on an older building – perhaps the oldest stone church in Sweden.

St. Olaf’s design is remarkable, the choir is both larger and longer than the nave. The idea might have been to build a long house as grand as the choir but for some reason that did not happen. The building came to a halt, perhaps due to a lack of funds.

Next to the church’s south wall, foundations of a small house with a dry well is still visible today. The little house was built earlier than the church and may have been built over a holy spring, a St. Olaf Spring.

During the Middle Ages, as many as seven large stone churches were erected by merchant guilds and wealthy townspeople. Today, the ruins of three remain: St. Peter’s, St. Lawrence’s, and St. Olaf’s (S:t Per, S:t Lars, and S:t Olof).