print could be used for propaganda in the Reformation for particular agendas, although the term propaganda derives from the Catholic Congregatio de Propaganda Fide (Congregation for Propagating the Faith) from the Counter-Reformation. Reform writers used existing styles, cliches and stereotypes which they adapted as needed. Especially effective were writings in German, including Luther's translation of the Bible, his Smaller Catechism for parents teaching their children, and his Larger Catechism, for pastors. Using the German vernacular they expressed the Apostles' Creed in simpler, more personal, Trinitarian language. Illustrations in the German Bible and in many tracts popularised Luther's ideas. Lucas Cranach the Elder (1472–1553), the great painter patronised by the electors of Wittenberg, was a close friend of Luther, and he illustrated Luther's theology for a popular audience. He dramatised Luther's views on the relationship between the Old and New Testaments, while remaining mindful of Luther's careful distinctions about proper and improper uses of visual imagery. Causes of the Reformation The following supply-side factors have been identified as causes of the Reformation: The presence of a printing press in a city by 1500 made Protestant adoption by 1600 far more likely. Protestant literature was produced at greater levels in cities where media markets were more competitive, making these cities more likely to adopt Protestantism. Ottoman incursions decreased conflicts between Protestants and Catholics, helping the Reformation take root. Greater political autonomy increased the likelihood that Protestantism would be adopted. Where Protestant reformers enjoyed princely patronage, they were much more likely to succeed. Proximity to neighbours who adopted Protestantism increased the likelihood of adopting Protestantism. Cities that had higher numbers of students enrolled in heterodox universities and lower numbers enrolled in orthodox universities were more likely to adopt Protestantism. The following demand-side factors have been identified as causes of the Reformation: Cities with strong cults of saints were less likely to adopt Protestantism. Cities where primogeniture was practised were less likely to adopt Protestantism. Regions that were poor but had great economic potential and bad political institutions were more likely to adopt Protestantism. The presence of bishoprics made the adoption of Protestantism less likely. The presence of monasteries made the adoption of Protestantism less likely. A 2020 study linked the spread of Protestantism to personal ties to Luther (e.g. letter correspondents, visits, former students) and trade routes. Reformation in Germany In 1517, Luther nailed the Ninety-five theses to the Castle Church door, and