Protestantse Kerk in Nederland (Reformed)
Appingedam was the most important port in Groningen during the Middle Ages with its open waterway to the sea. The Nicolaikerk dates from around 1225. It was originally dedicated to Our Lady, but changed to Saint Nicholas, the patron of bargemen and merchants, around 1408. This happened as Appingedam became an important commercial center. Through the centuries the church has been altered significantly. Though the frescos were plastered over after the Reformation, some have been restored. There is a fresco of Saint Nicholas on the vault of the apse.