Anacrusis

Anacrusis is the initial unstressed syllable or syllables of a verse line before the first metrical stress (ictus). The concept helps to describe the rhythmic onset of a poem and to reconcile different measures: by their anacrusis the trochee (zero anacrusis) differs from the iamb (monosyllabic anacrusis), and the dactyl from the amphibrach and anapaest. A fixed or variable anacrusis substantially affects the intonational movement of the line's opening and the overall rhythmic impression. In tonic and transitional versification the variation of anacrusis is one means of rhythmic diversification. The analysis of anacrusis is important for the precise determination of metre, especially in texts with an indistinct or mobile stress boundary at the beginning of lines.