Pruszków was incorporated as a town in 1916 during World War I, although the village was first mentioned in chronicles in the 15th century. Within the Polish Crown, it was a private village of Polish nobility, administratively located in the Masovian Voivodeship in the Greater Poland Province. The development of the town was aided by the construction of the Warsaw-Vienna Railway in the 19th century and the construction of the Elektryczna Kolej Dojazdowa (now Warszawska Kolej Dojazdowa), Poland's first electrified commuter train line, in 1927. In the late 19th century, industry developed intensively in Pruszków. There were needles, porcelain, faience, and soap factories in Pruszków. A large psychiatric hospital opened in the outlying village of Tworki in 1891 and is still operating to this day. During World War I, a battle between German and Russian forces took place in Pruszków on 12–18 October 1914 (part of Battle of the Vistula River). Despite the initial success of the German forces on 12 October, they were push-backed out of town after successful Russian counter-attack on 14th. An intense artillery fire by both sides caused severe damages to many buildings in Pruszków including train station, power plant, and two churches. In August 1915 Pruszków was taken by the German forces without a fight. Within interwar Poland, it was administratively located in the Warsaw County in the Warsaw Voivodeship.