It is not easy by any means to obtain prosodic information from documents written in ancient languages because it is not usually recorded therein. But the techniques of philology and linguistics sometimes enable us to derive prosodic evidence from written data. The two lenition rules in Proto-Anatolian, which were considered to have operated either after an accented long vowel or between two short vowels, have been unified by Adiego into a single rule in moraic terms: lenition occurred after an unaccented mora. Furthermore, Hittite mediopassive present verbs of the nasal-infix class, which cannot be adequately accounted for on the supposition that the basic units which carried accents in Proto-Anatolian were syllables, come to receive a well-motivated (both morphologically and typologically) and straightforward historical explanation from a moraic point of view. These two independent pieces of evidence inevitably lead us to argue that Proto-Anatolian was a mora-based language.