1. Dactylic Hexameter

2. Dactyl: long syllable, two short syllables
vertice

3. Hexameter
Six measures
In this case, six feet
For instance:

4. Spondees!
Despite the name, any dactyl can be replaced by a spondee

5. Endings The last foot is never a dactyl
The fifth foot is rarely a spondee
So almost all lines end like this:
Tum tiddy tum tum!

6. Anceps / Brevis in Longo
We give the name Anceps to any position in a line of verse that can have a long or short syllable
The last syllable of the hexameter is Anceps – it can be short or long
It's often marked like this:
Note: when short, this syllable is also called brevis in longo – a short in place of a long. The theory is that the end of the line acts like a final consonant and lengthens the syllable by position...

7. Notation
We can diagram the full range of possibilities for the hexameter like this:

8. Practice Without further ado, lets practice a few lines:
mille domos adiere locum requiemque petentes

9. mille domos adiere locum requiemque petentes

10. First syllable is long (has to be in dactylic hexameter – you can rely on this!!!
Next two are short – dactyl complete!
mille domos adiere locum requiemque petentes

11. 2nd declension plural accusative ending -os is long
And the first syllable of the foot has to be long anyway
Looks like another dactyl to me...
mille domos adiere locum requiemque petentes

12. That first e in adiere is long because it's the alternate form of the 3rd person plural perfect, adierunt
mille domos adiere locum requiemque petentes

13. -cum is long because it's followed by two consonants
Note that qu- in requiem acts like a single consonant
mille domos adiere locum requiemque petentes

14. -em in requiemque is long by position, since it's followed by -mq-
mille domos adiere locum requiemque petentes

15. So it's all dactyls apart from the last, which can't be a dactyl.
mille domos adiere locum requiemque petentes

16. Another one:
illa sunt annis iuncti iuvenalibus, illa

17. illa sunt annis iuncti iuvenalibus, illa

18. illa sunt annis iuncti iuvenalibus, illa
Ablative singular, 1st declension ends with long ā
illa sunt annis iuncti iuvenalibus, illa

19. An important tip illa sunt ...
Let's say we aren't sure that illa is meant to be ablative – maybe it's nominative
In that case, it would be short a.
But that would leave us with this pattern:
That pattern (it's called a cretic) never occurs in dactylic hexameter
So if the syllables on either side are long, this one must be too! And so it must be ablative – by reading for meter, we just figured out the grammar.
illa sunt ...

20. illa sunt annis iuncti iuvenalibus, illa
Both long by position (vowels followed by more than one consonant)
illa sunt annis iuncti iuvenalibus, illa

21. illa sunt annis iuncti iuvenalibus, illa
Ablative plural first and second declension end with long īs
The u in iuncti is long by position
illa sunt annis iuncti iuvenalibus, illa

22. illa sunt annis iuncti iuvenalibus, illa
The I that starts iuvenalibus is a consonant here
illa sunt annis iuncti iuvenalibus, illa

23. illa sunt annis iuncti iuvenalibus, illa
If you didn't know before that the a in iuvenalibus is long, you'd know now, since you need it to start your foot!
illa sunt annis iuncti iuvenalibus, illa

24. illa sunt annis iuncti iuvenalibus, illa
So, more spondees in this one
illa sunt annis iuncti iuvenalibus, illa

25. Caesura One final thing to learn
In most latin meters, the lines are put together from two half-lines
Some people call those part-lines cola
Where the parts join, there's usually a natural break in sense
At the very least, it's a break between words
We call that the caesura, and we mark it like so:

26. Note: for some, the caesura marks a point in the line where someone reading the poem out loud would pause for breath
This doesn't seem to make much sense when we find poets eliding syllables before the caesura
So just think of it as the point where the line has been glued together from its components

27. Position
In dactylic hexameter, the caesura most often occurs after the first syllable of the third foot
It's quite common after the first syllable of the fourth foot
Occasionally it occurs between the two short syllables of a dactyl in those feet (sometimes called a “weak” caesura). That's really rare in the fourth foot.

28. Updated Notation

29. Our first example
We don't want to break up “locum requiemque” since that's a pair
So the caesura makes most sense after adiere – a so-called weak caesura
mille domos adiere locum requiemque petentes
mille domos adiere locum requiemque petentes
mille domos adiere locum requiemque petentes

30. illa sunt annis iuncti iuvenalibus, illa
This one's debatable (the position of the caesura often is)
It would work well in the middle of the fourth foot too
illa sunt annis iuncti iuvenalibus, illa