A preposition is a word in front of a noun. The preposition does not decline, but it changes the case of the noun that follows it.

Most prepositions are followed by a noun in the accusative or the ablative case. Some can be followed by a noun in either case, depending on their meaning.

Prepositions + accusative

ad towards, to, for, at
ante before
apud at, by, near, to, towards
inter among, between
iuxta next to, near, according to
per by, through, during
post after

Prepositions + ablative

a (before a consonant) / ab (before a vowel) by, from
coram in the presence of, before
cum with
de from, concerning, of, for
e (before a consonant) / ex (before a vowel) from, out of
pre before
pro for, during, as far as, in accordance with, in return for
sine without

Prepositions + accusative or ablative

in + accusative into, onto
in + ablative in, on
super + accusative over
super + ablative upon

The meaning of these preposition changes, using

  • accusative to describe movement towards something
  • ablative to describe the position of something which is static

One of the main differences between medieval Latin and Classical Latin is the increased use of prepositions.

In Classical Latin, a phrase would be given using the noun with the appropriate case ending.

In medieval Latin, the same phrase may be given using a noun and a preposition, particularly ad, de, per and pro.

For example
‘the bishop of York’

episcopus Eboraci Classical Latin – using the genitive case to express ‘of’.
episcopus de Eboraco Medieval Latin – using the preposition de to express ‘of’. de is followed by the ablative case.