13. _In post-Plautine Latin_ words accented on the ante-antepenult:--
(i.) suffered syncope in the short syllable following the accented syllable (_bálineae_ became _bálneae_, _puéritia_ became _puértia_ (Horace), _cólumine_, _tégimine_, &c., became _cúlmine_, _tégmine_, &c., beside the trisyllabic _cólumen_, _tégimen_) unless
(ii.) that short vowel was _e_ or _i_, followed by another vowel (as in _párietem_, _múlierem_, _Púteoli_), when, instead of contraction, the accent shifted to the penult, which at a later stage of the language became lengthened, _pariétem_ giving Ital. _paréete_, Fr. _paroi_, _Puteóli_ giving Ital. _Pozzuoli_.
The restriction of the accent to the last three syllables was completed by these changes, which did away with all the cases in which it had stood on the fourth syllable.
14. _The Law of the Brevis Brevians._--Next must be mentioned another great phonetic change, also dependent upon accent, which had come about before the time of Plautus, the law long known to students as the _Brevis Brevians_, which may be stated as follows (Exon, _Hermathena_ (1903), xii. 491, following Skutsch in, e.g., Vollmöller's _Jahresbericht für romanische Sprachwissenschaft_, i. 33): a syllable long by nature or position, and preceded by a short syllable, was itself shortened if the word-accent fell immediately before or immediately after it--that is, on the preceding short syllable or on the next following syllable. The sequence of syllables need not be in the same word, but must be as closely connected in utterance as if it were. Thus _modo_ became _módo_, _voluptatem_ became _volu(p)tatem_, _quid est?_ became _quid est?_ either the _s_ or the _t_ or both being but faintly pronounced.
It is clear that a great number of flexional syllables so shortened would have their quantity immediately restored by the analogy of the same inflexion occurring in words not of this particular shape; thus, for instance, the long vowel of _ama_ and the like is due to that in other verbs (_pulsa_, _agita_) not of iambic shape. So ablatives like _modö_, _sono_ get back their -_o_, while in particles like _modo_, "only," _quomodo_, "how," the shortened form remains. Conversely, the shortening of the final -_a_ in the nom. sing. fem. of the _a_-declension (contrast _luna_ with Gr. [Greek: chôrã]) was probably partly due to the influence of common forms like _ea_, _bona_, _mala_, which had come under the law.