The Nieuwe Kerk was built in 1649 after the Great Church had become too small. Construction was completed in 1656. The church was designed by the architect Peter Noorwits, who was assisted by the painter and architect Bartholomeus van Bassen. The church is considered a highlight of the early Protestant church architecture in the Netherlands. Like many churches of that time was the New Church, a central building. Unlike other central building, the church is no simple circular or multifaceted plan but there is a space of two octagonal sections which are connected by a slightly smaller proportion in which the pulpit was prepared. The architecture of the church shows elements of both Renaissance and Classicism. Two church bells by Coenraat Wegewaert in 1656 hang in their original bell-chairs.
The church has an organ built by the Dutch organ builder Johannes Duyschot (1645-1725) in 1702. The construction has left most of the pipework and the cupboard. The organ was rebuilt in 1867 by one of the best organ builders of that time, the business of Christian Gottlieb Friedrich Witte. They adjusted the design of the organ to make it suitable for modern Romantic music.
The Nieuwe Kerk contains the tombs of the brothers De Witt and of the philosopher Spinoza. Spinoza's tomb is in the churchyard.References:
Kristiansten Fortress was built to protect the city against attack from the east. Construction was finished in 1685. General Johan Caspar von Cicignon, who was chief inspector of kuks fortifications, was responsible for the new town plan of Trondheim after the great fire of 18 April 1681. He also made the plans for the construction of Kristiansten Fortress.
The fortress was built during the period from 1682 to 1684 and strengthened to a complete defence fortification in 1691 by building an advanced post Kristiandsands bastion in the east and in 1695 with the now vanished Møllenberg skanse by the river Nidelven. These fortifications were encircled by a continuous palisade and thereby connected to the fortified city. In 1750 the fortress was modernized with new bastions and casemates to protect against mortar artillery.