used for the subject of the verb;

what is doing the verb

i.e.     regina orat.             The queen prays. 

used to call or address someone

i.e.    O domina!                Oh lady!

used for the object of the verb;

what the verb is done to

i.e.    Domina cartam confirmat.

           The lady confirms the charter.
 

nouns that are of something or to show possesion

i.e.    terra ecclesie            The land of the church

         fillie vidue                the daughters of the widow
 

nouns that are to or for something

i.e.    terram ecclesie do.

           I give land to the church.
 

nouns that are by, with, or from something

i.e.    papa ecclesiam carta confirmat

           The pope confirms the church by a charter.