Institutio Oratoria

For the mere fact that words are separated from each other involves an imperceptible length of time: for instance, the spondee forming the middle foot of a pentameter must consist of the last syllable of one word and the first of another, otherwise the verse is no verse at all. It is permissible, though less satisfactory, for the spondee to be preceded by an anapaest: e.g. muliere non solum nobili, verum etiami nota. [*](pro Cael. xiii. 31. A woman, not only of noble birth, but even notorious. )

Andit may also, in addition to the anapaest and cretic, be preceded by the iambus, which is a syllable less in length than both of them, thus making one short syllable precede three long. But it is also perfectly correct to place a spondee before an iambus, as in armis fui, or it may be preceded by a bacchius instead of a spondee, e.g. in armis fui, [*](pro Lig. iii. 9. I was in arms. ) thereby making the last foot a dochmiac.