Storkyrkan (, ), also called Stockholms domkyrka (Stockholm Cathedral), is the oldest church in Stockholm. Storkyrkan lies in the centre of Stockholm in Gamla stan, between Stockholm Palace and Stortorget, the old main square of Stockholm. It was inaugurated in 1306 but construction of the church probably started in the 13th century. Inside, Storkyrkan still maintains much of its late medieval appearance in the form of a hall church with a vaulted ceiling supported by brick pillars. The exterior of the church is however uniformly Baroque in appearance, the result of extensive changes made in the 18th century. During the Middle Ages, it was dedicated to Saint Nicholas, but after the Reformation in Sweden – in which the church played an important role as the place where Mass was celebrated in Swedish for the first time – it has been a Lutheran church, not formally dedicated to any saint. It currently serves as the seat of the Bishop of Stockholm within the Church of Sweden since the creation of the Diocese of Stockholm in 1942.