The Latin relative pronoun looks like this:
Case \ Gender: masculine : feminine : neuter singular
Nominative: qui : quae : quod
Genitive: cuius : cuius : cuius
Dative: cui : cui : cui
Accusative: quem : quam : quod
Ablative: quo : qua : quo
Plural:
qui : quae : quae
quorum : quarum : quorum
quibus : quibus : quibus
quos : quas : quae
quibus : quibus : quibus
Note that the nominative and accusative of the neuter are always identical.
The relative pronoun takes the case according to its role within the relative clause, but its gender and number according to what it relates to within the main clause.
Exercise. We’ll focus on the nominative and the accusative, for now. Convert the two main clauses into a main clause and a relative subordinate clause as in the examples, and translate the result into english. Again, nevermind the word order, important is agreement of Case, Number, Gender; however, put the relative pronoun at the beginning of its clause, just like you would in english.
Titus Marcum vidit . Marcus Corneliam amat. > Titus vidit Marcum, qui amat Corneliam ‘Titus sees Marcus, who loves Cornelia,’
Titus vidit Marcum. Marcum amat Cornelia > Titus vidit Marcum, quem amat Cornelia ‘Titus sees Marcus, whom Cornelia loves.’
Marcus adspectat Corneliam. Marcus Corneliam amat. > Marcus adspectat Corneliam, quam amat ’ Marcus awaits Cornelia, whom he loves’.
Your turn!
Feles edit murem. Feles murem cepit (caught). (replace murem here)
Hic est filius meus. Valde amo filium meum.
Brennus puer valde immodestus est. Brennus non adiuvat matrem suum.
Spiritus te defendit a monstris. Monstra te devorabunt.
Virum cognoscimus. Vir in Italiam venit.
Galli in pace vivebant. Caesar Gallos vincit.