The Château de Serrant is a Renaissance château built on the foundations of a medieval fortress. From the 14th century the castle was held by the Brie family. Charles de Brie was inspired to start modernisation early in the 16th century, but lack of funds meant the project was halted with only the North Tower completed.
Ownership of the castle then changed hands several times before Guillaume de Bautru, a State Councillor, purchased the property in 1636. de Bautru restarted the construction that had been halted over a century earlier. By using Charles de Brie's original plans and the same russet schist and white tuffeau stone, de Bautru ensured that there was a continuity of design. The central halls, two wings and the South Tower were added, with Jules Hardouin Mansart completing the work of de Bautru by building the chapel.
In 1749, the estate was sold by the last surviving descendant of the de Bautru family and was bought by Antoine Walsh, a shipowner whose family were exiled Jacobites. As well as redecorating the interior of the castle, the Walsh family built an English style park, pavilions, and a monumental gate complete with the family crest. The château eventually passed out of the hands of the Walsh family in 1830 when Valentine Walsh de Serrant married the Duc de La Trémoïlle. La Trémoïlle assigned Luciene Magne the task of restoring the castle and several features, including parapets and cornices, were added. The La Trémoïlle family still own the château, but in the 20th century it has been modernised with cellars and the introduction of electricity.
The castle is notable for the library, stocked with 12,000 books; the vaulted halls, originally home to the kitchens; and Napoleon's bedroom, which was never used by the Emperor as he stayed at the castle for only two hours.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.