Modlin Fortress () is one of the largest 19th-century fortresses in Poland. It is located in the town of Nowy Dwór Mazowiecki in district Modlin on the Narew river, approximately 50 kilometers north of Warsaw. It was originally constructed by the French from 1806 to 1812. History The strategic importance of the area limited by the Vistula, Bug, Wkra and Narew was known to various armies throughout the ages. The first fortified stronghold was built in Zakroczym by the Piast dynasty in the 11th century. However, first modern fortified position was built there in 1656 by the Swedish armies during The Deluge. The so-called Bugskansen was a star-shaped fortified military camp, located probably close to the confluence of the Narew and the Vistula, at the so-called Swedish Island. The camp was also guarding a wooden bridge over the Vistula prior to the battle of Zakroczym and served as the main supply depot of the Swedish army during the battle of Warsaw of July 1656. After the Swedish defeat the fort was demolished in 1660 and the area remained unfortified for roughly 150 years. After the Partitions of Poland the area was incorporated into the Russian Empire. Shortly afterward Jan Pieter van Suchtelen, a Dutch military engineer in Russian service prepared a construction plan for a mighty fortress in the area, named after the nearby town of Zakroczym. The fort was to be a bastion fortress, located approximately 1.5 km from the rivers and with several forts guarding the area from the west. However, the project was never accomplished as in 1806 the area became part of the Duchy of Warsaw, a rump Polish state created by and allied to Napoleon Bonaparte. From the very beginning of French presence in Poland, Bonaparte's engineers started to fortify the border with Russia, expecting either a Russian offensive towards western Europe – or a future offensive of the French armies towards Petersburg and Moscow. In December 1806, while in Poznań, Napoleon ordered a fort to be built on two islands located at the confluence of the Narew and the Vistula. The fortification was to be temporary and was to become primarily a supply depot and a huge granary, serving as a supply centre for the forces operating in Poland or Russia. The construction started almost immediately, although Chief Engineer of the French forces Gen. François de Chasseloup-Laubat decided to build the fortress on the