Description: My DPhil research focuses on the development of Latin's philosophical vocabulary, specifically from the perspective of lexical innovation and translation. This linguistic phenomenon includes a range of techniques employed by authors to render Greek technical terminology into Latin. The obvious, though in fact quite rare, is neology, but another is the semantic extension of existing Latin terms to include Greek concepts and the use of metaphor. How was the need for a new philosophical lexicon (as Lucretius famously bemoaned: the patrii sermonis egestas) balanced against the contingencies of Roman linguistic purism? The thesis explores five authors over 600 years of Latin philosophical translation, from Cicero to Boethius, with such questions in mind, collating a substantial number of lexical innovations in Latin philosophical vocabulary into a single source for the first time, as well as adding to, and re-evaluating, past studies in the field.