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 northern bank of the river rather than on the islands. The work started in early 1807, yet went on very slowly. It was not until the following year that the pace was speeded up and in 1809 the first casemates and walls were ready. It was there that the core of the Polish Army was stationed after the Battle of Raszyn against the invading forces of Austria. Soon after the outer rim of defences on the right bank of the Vistula was ready. It ran more or less along the inner line of modern fortifications. It consisted of a semi-circular earthwork reinforced with wooden stockade and five bastions. In addition, the area was guarded by two fortified bridgeheads, one in Kazuń on the left bank of the Vistula and the other next to Nowy Dwór Mazowiecki.
In 1810 the very concept of the fort was changed and Napoleon decided to turn Modlin into a pivotal fortress in his line of fortifications and expand it significantly by adding an outer rim of defenses. General de Chasseloup-Laubat was replaced with a famous French engineer Jean Mallet de Granville (later a naturalized Pole under the name of Jan Malletski), aided by Gen. François Haxo. It is not certain whether the authors of the expansion were the two to supervise its construction, or Napoleon himself. The works continued on a very fast pace as Napoleon was planning his campaign in Russia and envisioned Modlin to become the main fortress behind his lines. By September 1811 more than 19,000 people were taking part in the works. Because of that the authorities of the Duchy of Warsaw were considering to grant Modlin with a city charter, which however did not succeed. Although the following year, shortly before the outbreak of the Franco-Russian War, the number of workers exceeded 20 thousands, the fortress was never fully completed.