In addition to his medical works, Arnau also wrote many others on a wide variety of topics and with widely divergent characteristics, including commentaries on other works, interpretations of divine tetragrams, texts denouncing religious fakes, apocalyptic works, polemics, sermons and letters. Generically speaking they tend to be called “spiritual works”, “theological works” or “religious works”, even though their topics and style do not always match these descriptions. hese works were written in latin or catalan and some were soon translated into other languages, such as Greek, Italian (Tuscan and Neapolitan) and Castilian (Spanish). The 1316 Tarragona ruling condemned numerous theses contained in these texts, and thus few manuscripts remain today. Some of his works have not survived. On the other hand, there are reasons for doubting the authenticity of some texts which have been transmitted under his name.

Clement V
Illustration: The Templars before Pope Clement V and King Philippe IV of France during the Council of Vienna, in which the pope abolished the Order of the Temple at the instigation of Philippe (1311-1312).Londres, British Library, Cotton Nero E II, pt 2, f. 100v. Arnau presented Clement V, a personal friend of his, with a manuscript of his spiritual Latin works in 1305, just after he was elected pope, and the set is in a Vatican manuscript today. Arnau intervened in the Templar affair, as we can see through numerous letters addressed to Clement V, Jaume II and Philippe IV.