The earth and timber stronghold Gerdauen was constructed by the Teutonic Knights in 1270. After a subsequent Prussian uprising, the Knights were too weak to keep hold of all their fortresses. Gerdauen was burnt down, but once the Prussian uprising was put down, the Teutonic Knights returned here and began to raise new fortifications. By 1310, a new stronghold had been completed. At that time it was guarded by embankments, moats and shelters. Inside the ring of fortifications, stone and brick buildings for a convent of Teutonic brothers were constructed.
Initially the Knights planned that Gerdauen would become a seat of a commander, known as komtur. But this idea was soon relinquished because of the proximity to the Lithuanian lands and frequent attacks staged by Lithuanian troops. Gerdauen for example was attacked in 1336, 1337 and in 1366.
Although in 1406 Gerdauen Castle was surrounded by a ring of fortified walls less than half a century later, in 1455, which was during the Thirteen Years' War, the fortress was severely damaged. In 1670 it stood empty. Soon afterwards it was sold to a private owner. All that had remained of the original buildings were the cellars.
In 1872 a new beautiful palace was raised on this location. Gerdauen flourished until 1814, that is until the outbreak of World War One. In that year, the town was a witness and a victim of a bloody fight with the Russian army. Gerdauen was not rebuilt until 1921.
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.