The Fraeylemaborg was one of the most important borg in the province of Groningen. These strong houses or keeps were built in the Middle Ages to store harvests and to protect their produce from robbers. Besides churches, these structures were the only buildings that used durable stone and masonry. In due time they grew to become centres of power and wealth. The Fraeylemaborg is located in the middle of the town of Slochteren which upon its discovery in 1959 gave its name to the largest gasfield in the world.
In 1475 there was already a farm with the name Frealemaheerd. The building originates from the 16th century. The left wing was built in the 17th century. In 1680 the borg was sold by Evert Rengers, son of the former lord of the manor, because of his family debts. It was bought by Henric Piccardt (married to Anna Elizabeth Rengers, Evert's sister), who borrowed the necessary funds from Stadtholder William III. Piccardt extensively rebuilt the borg and he also landscaped a huge formal garden in the style of Louis XIV's France. After Piccardt's death the borg fell into disrepair. In 1781 the Fraeylemaborg was sold to Hendrik de Sandra Veldman. He rebuilt it into the shape it has today. Among his innovations was the removal of two towers which had graced the front square.
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.