The pagan societies of Scandinavia were only completely converted to Christianity in the 12th century AD. The battle for Christianity produced native saints: kings who fell defending the faith, such as Olaf Haraldson of Norway (died 1028), and the martyred St Cnut IV of Denmark (died 1085). However, once Christianity became dominant, feasts such as Christmas and Easter were readily accepted in place of pagan winter and spring festivals.

At the Reformation, the Scandinavian countries adopted Protestantism. Sweden was an early convert. At the Synod of Uppsala in 1593, the Catholic rite was abolished and the state religion became Lutheran. Lutheranism was not as rigorous as some of the more severe forms of Protestantism: veneration of the Virgin Mary and saints continued, particularly in the country where people still celebrated their local saints and festivals.

The importance of the Church year was reflected in the production of accurate calendars. The earliest were carved on wooden staves. They included details of the seasons and the movements of the sun and the moon – important for fishermen and farmers. The wooden calendars were gradually replaced with printed almanacs, but the same sort of information, the attention paid to the seasons, and the use of the old pagan runic symbols to mark the days continued into the 19th century.