was founded, and in the late 19th century the city began to industrialize. In 1863 local Poles fought in the January Uprising against Russia. The leader of the uprising in the Płock region, Zygmunt Padlewski, was executed by the Russians in Płock in May 1863. In 1905, large demonstrations of Polish youth and workers took place in Płock. During World War I, Płock was occupied by Germany from 1915 to 1918, and in 1918 Poland regained independence, and Płock was immediately reintegrated with Poland. In August 1920, the city became famous for its successful heroic defense against the Soviets during the Polish–Soviet War. 250 Polish defenders, including 100 civilians, were killed in the battle. In 1921, Marshal Józef Piłsudski visited Płock and awarded the city with the Cross of Valour, making Płock the second Polish city to be awarded with a Polish military decoration (shortly after Lwów). World War II Germany invaded Poland in September 1939, the city of Płock was annexed into the Reich as part of the Regierungsbezirk Zichenau. The Germans renamed the city Schröttersburg in 1941 after the former Prussian Baron of the Empire Friedrich Leopold von Schrötter. As part of the Intelligenzaktion, the Germans carried out mass arrests of Poles, who were then imprisoned in the local prison, and around 200 of whom were murdered in large massacres in Łąck between October 1939 and February 1940. Among the victims were Polish teachers, activists, shopowners, notaries, local officials, pharmacists, directors and members of the Polish Military Organisation. Next mass arrests of about 2,000 Poles from Płock and the Płock County were carried out in April 1940, and in June 1940, another 200 Poles from various settlements in the region were imprisoned in the local prison. Some prisoners were then deported and murdered in the Soldau concentration camp, and some teachers from Płock were among Polish teachers murdered in the Mauthausen concentration camp. In 1940, Germans murdered 80 elderly and disabled people from Płock in the nearby village of Brwilno. The Archbishop of Płock Antoni Julian Nowowiejski and the auxiliary Bishop Leon Wetmański were imprisoned in the nearby village of Słupno, and then in 1941 also murdered in the Soldau concentration camp, where also many other local priests were killed. Nowowiejski and Wetmański are now considered two of the 108 Blessed Polish Martyrs of World War II by the Catholic Church. Poles were also subjected to expulsions, 1,300