A syllable may be either long or short. If long, then it is either long by nature or by position:

• Nature: A syllable is long by nature if it has a long vowel or a diphthong.
• Position: A syllable is long by position if it has a vowel followed by two or more consonants.
• These two or more consonants can be in different words. So with "hic mīles" the hic is long by position (the i is followed by the c and m, even though they are in separate words), while the ī in mīles makes mī- long by nature.)

Note the following special points:

• x (c+s) and z (d+s) count as two consonants and so the vowel coming before it makes the syllable long. Hence dux is long.
• h is an aspirate only and is not a consonant for our purposes, so you can effectively ignore the h when determining syllable length. (the first syllable in ad hoc, for example, is short)
• qu counts as a single sound, and does not by itself make the preceding vowel long. Be careful of the u in the qu: it is not a vowel. So the word e-quus, for example, has two syllables, not three, and the first syllable (e-) is short; but the word linquere has three syllables (lin-que-re) and the first syllable (li-) is long by position.
• Pay close attention to i, which can be either a vowel or a consonant (but never at the same time!).
• If the two consonants are a stop (p, t, c, b, d, g) followed by a liquid (l, r) the syllable coming before can be treated as either long or short for metrical purposes, and you will often see the author take advantage of this.

When a final vowel or a vowel followed by m occurs at the end of one word, and another vowel or a vowel preceded by h occurs at the beginning of the next word, the first vowel (or vowel + m combination) is regularly elided – which means that either the syllable itself is not pronounced at all, or so lightly that it does not count for metrical purposes. This is called elision and it happens quite a bit in epic. On rare occasions the first vowel is not elided and both syllables retain their natural lengths. This is called hiatus. Most poets usually try to avoid it, but it is sometimes used for special effect.

Examples:

• quoque et becomes quoqu-et
• multum ille becomes mult-ille
• atque hominum becomes atqu-hominum
• animam hanc becomes anim-hanc

Sometimes you will find a short syllable treated as long or a long syllable treated as short for no real reason other than because it has to be. Lengthened short syllables are most likely to occur at the beginning of a metrical foot or before a significant metrical pause.

A hexameter verse consists of six metrical feet, each of which contains either a long syllable followed by two short syllables (a dactyl) or two long syllables (a spondee). The basic pattern is

Note that the last (sixth) foot in the line can almost always be treated as a spondee, and the last syllable is in the line usually counts as long for metrical purposes, regardless of its natural length. Sometimes this final syllable is naturally short and this foot can be considered a trochee (long-short). The fifth (next-to-last) foot is usually a dactyl, although a spondee can be used for special effect.

1. The eu diphthong is used in short exclamations (like heus) and Greek names (like Odysseus, which has three syllables). Don’t confuse this diphthong with nouns where the e is part of the stem (and is short) and the u is part of the ending, like mĕ-us and ĕ-unt, which are both disyllabic.
2. Likewise, the ui diphthong is used in short words like cui and huic. Don’t confuse this diphthong with nouns where the u is part of the stem (and is short) and the i is part of the ending, like sŭ-īs and ē-mĭ-cŭ-it.
3. It’s not as easy to double check to make sure your scanning line is correct, but there are three steps you can take to make sure you haven’t made egregious errors:
   • Check to make sure you have six feet in a line. If you have seven, you need to change some long syllables into shorts. If you have five, you need to change some short syllables into longs.
   • Check to make sure you haven’t missed an elision, especially ones where the first word ends in an -m and/or the following word begins in an h-.
   • Look for mistakes with the two consonant rule. Often, correcting this and making a vowel followed by two consonants long will fix your line.
   • And last but not least, look for your caesura. There should be a natural break after the first long syllable in the foot, either at one-and-a-half, two-and-a-half, or three-and-a-half. If you find that your word ends when the foot ends, especially at the end of the second or third feet, your line is likely wrongly scanned.