The historiography of Reformation attitudes to marriage and ministry, and the related issue of clerical marriage, is substantial. The denunciation of compulsory clerical celibacy was not simply a criticism of the morality of the contemporary clergy, but a condemnation of the doctrine, traditions, and structures of the medieval church. Debate over clerical celibacy and marriage was undoubtedly fuelled by the marriage of several evangelical leaders in the 1520s. The actions of the married priests in Wittenberg encouraged further debate, and the first full-length defence of clerical marriage, Carlstadt's Axiomata Super Coelibatu, Monachatu et Viduitate, was printed in 1521. The Zurich council had petitioned the bishop to take action against unworthy priests as early as 1507, and further appeals were made to the bishop of Constance to act against clerical concubinage in 1512. This focus on clerical marriage as a divinely sanctioned solution to the undesirable consequences of clerical celibacy remained a commonplace of evangelical writing.