 Since the Restoration More had concentrated exclusively on religious writings, some of which were demanded by the writings of his critics. In 1667, however, he produced a work on moral philosophy, the Enchiridion ethicum. It is known that More wrote Latin with difficulty, and it is not clear why he did not publish this in English. It is possible that he hoped to reach a wider, European audience—certainly this would be the motivation, a few years later, for translating his earlier works into a Latin Opera omnia (1675–79)—but this seems an unlikely book with which to introduce oneself to a European readership. There is another possible explanation, with much more restricted local concerns: More published it in Latin to leave room for his friend and colleague Ralph Cudworth to publish his very similar system of ethics in English.