The Martinikerk is the oldest church in Groningen, Netherlands. The church and its associated tower are named after Saint Martin of Tours, the patron saint of the Bishopric of Utrecht to which Groningen belonged. The church was a cathedral for a short period during the first bishopric of Groningen. The origins of the Martinikerk are a cruciform church built in the 13th century, which was extended in the 15th and 16th centuries.