Originally there was a chapel situated on the site of the current Aa-kerk church. This chapel was devoted to Mary and to Saint Nicholas, the patron of the bargees who cast off the vessels at the Westerhaven.
In 1247, the chapel became the parish church and was named Onze Lieve Vrouwe ter Aa (Our Lady at the Aa) - Aa being the nearby river. Groningen had two centers at the time. One of them was around the chapel. Here lived the fishermen and the traders. Between 1425 and 1465, the chapel was changed into a brick church with a transept.
Images of the Siege of Groningen in 1672 show Der Aa-kerk without the top of the tower. After the war a new wooden tower top was built. On 23 April 1710, the tower spontaneously collapsed killing two people. In 1711, a new tower was built.References:
The Broch of Gurness is an Iron Age broch village. Settlement here began sometime between 500 and 200 BC. At the centre of the settlement is a stone tower or broch, which once probably reached a height of around 10 metres. Its interior is divided into sections by upright slabs. The tower features two skins of drystone walls, with stone-floored galleries in between. These are accessed by steps. Stone ledges suggest that there was once an upper storey with a timber floor. The roof would have been thatched, surrounded by a wall walk linked by stairs to the ground floor. The broch features two hearths and a subterranean stone cistern with steps leading down into it. It is thought to have some religious significance, relating to an Iron Age cult of the underground.
The remains of the central tower are up to 3.6 metres high, and the stone walls are up to 4.1 metres thick.