Round 1300 the chapel was enlarged with two transepts. Of this extension one capital survives.
It is placed to the right of the organ against the façade of the northern transept.

Around 1350 the western tower was constructed. Of this phase the brick stones are still visible in the lower embrasure of the tower.



Around 1390 at the back of the existing church a gothic hall choir with one main vessel and two aisles was built. Towards the end the 14th century permission was asked from bishop Frederic van Blankenheim to demolish the derelict old church. This involved the old court chapel with its extension. When this permission came in 1404, the old chapel was replaced by the tree aisle hall church. This church was consecrated in 1413. 

 

In 1438 a fire raged in town, but the church could quickly be repaired. The size in that hall church between the pillars was about half the size of the current church. Between each of the current pillars there used to be an extra pillar. One could say there was a wood of pillars topped by pointed arches. Of this hall church remnants survive and the exterior facades. The lower base of the brick facades as well as the porches in the northern- and southwesterly parts date from 1404. Around 1470 again a lack of space, due to the ever growing amount of altars, resulted in an extension of two extra side aisles and a transept.