When Sigtuna was founded by King Erik the Victorious around year 980, the intent was to seek control over people and create an empire like the European kingdoms. He already had the knowledge of building a town, but he needed the church to cooperate.

Erik was a modern Scandinavian king. The goal was a kingdom with one king and one God. He would be the king and head of the Church. The project was exciting and curious for the powerful men in the area of Sigtuna- a Christian city!
Sigtuna was founded to be the first Christian town in Sweden – the centre of the new religion.

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 (St. Per, St. Lars, and St. Olof).

Source; https://destinationsigtuna.se/