Question: What's an example of a caesura?
Answer: The first line of The Aeneid, the great Roman national epic, by Vergil (Virgil), begins with the famous line:
Ar-ma vi-|rum-que ca-|nō, Trō-|iae quī | prīmus ab| ōrīsIn this line, I've marked the long syllables with bolding and have put macrons on the vowels that are long by nature. A strong caesura comes in the middle of the line, at the end of the word canō, in the middle of the foot. The second syllable of canō is in a different foot from the start; it is the start of its own spondee (a foot consisting of 2 long syllables that is an acceptable substitute for a dactyl), and ends a clause. For these reasons, there is a strong caesura after the [ō].
There are other, weak caesurae after arma, que, Trōiae, and prīmus.
In contrast, there is a diaeresis after quī because the word end that is necessary for either a caesura or diaeresis is at the end of the foot.
