Danish mass media date back to the 1540s, when handwritten fly sheets reported on the news. In 1666, Anders Bording, the father of Danish journalism, began a state paper. In 1834, the first liberal, factual newspaper appeared, and the 1849 Constitution established lasting freedom of the press in Denmark. Newspapers flourished in the second half of the 19th century, usually tied to one or another political party or trade union. Modernisation, bringing in new features and mechanical techniques, appeared after 1900. The total circulation was 500,000 daily in 1901, more than doubling to 1.2 million in 1925. The German occupation during World War II brought informal censorship; some offending newspaper buildings were simply blown up by the Nazis. During the war, the underground produced 550 newspapers—small, surreptitiously printed sheets that encouraged sabotage and resistance.