 Medieval philosophical texts are written in a variety of literary forms, many peculiar to the period, like the summa or disputed question; others, like the commentary, dialogue, and axiom, are also found in ancient and modern sources but are substantially different in the medieval period from the classical or modern instantiations of these forms. Many philosophical texts also have a highly polemical style and/or seem deferential to the authoritative sources they cite. Further, medieval philosophical thinkers operated under the threat of censure from political and religious authority, moving them, some have argued, to write esoterically or indirectly to protect themselves from persecution for their true views. All these literary and rhetorical features make medieval philosophical texts considerably more difficult to understand and interpret than modern or even classical philosophical texts. Moreover, the broad range of genres used in medieval philosophy raises questions about the nature of philosophical writing in general when compared to the much more restricted set of accepted forms in modern and contemporary philosophical works.