The status of Trisyllabic Shortening or TRISH has been solid as a phonological process in historical phonology of late Old English and early Middle English since Luick (1921), who asserted that analogical leveling based on trisyllabic shortening was required to account for the exceptions to Middle English Open Syllable Lengthening or MEOSL. Minkova (1982) and Minkova and Stockwell (1996) have claimed, however, that MEOSL must be regarded as compensatory lengthening due to the loss of schwa in word-final position and that there is no place for TRISH in the quantity adjustment processes in early English. In line with Minkova (1982), Bermudez-Otero (1998) has proposed an Optimality-theoretic analysis of MEOSL and criticized the role of analogical leveling and in particular that of TRISH in the account of alternations within the inflectional paradigms of nouns in early English. The aims of the current paper are twofold: we will review the arguments of both sides over TRISH in phonological literature of early English; adopting Lahiri and Fikkert’s (1999) view that TRISH, interacting with MEOSL, played a crucial role as a prosodic constraint in the phonology of early English, we will propose a unified constraint system within Optimality that can account for MEOSL and TRISH.