On this page and the last, the word pictor appears numerous times. Let’s take a look.
pictor est! coquus pictorem salutat. coquus est pictoris amicus. coquus cibum pictori dat.
You’ll notice that in each of these sentences, the word pictor appears with a modified ending. That is because each example appears in a particular Noun Case. Each Noun Case has a job to do.
pictor is in the Nominative Case. It is the Subject of the Verb. It is ‘doing the action of the Verb’. Here, the pictor ‘is’. In the final sentence, pictor multas gratias coquo agit, pictor is again in the Nominative Case and is the Subject of the verb agit. He is driving thanks to the cook.
pictorem is in the Accusative Case. It is the Object of the Verb. It is ‘receiving the action of the Verb’. Here, the pictorem receives the action of greeting. coquus is in the Nominative Case and is the Subject.
pictoris is in the Genitive Case. Here the Genitive Case is signaling Possession, not unlike an apostrophe s in English. ‘The cook is the artist’s friend.’
pictori is in the Dative Case. There are numerous ways to describe what the Dative Case does. One is to suggest that it is ‘Indirectly Affected by the action of the Verb’. The Subject is coquus, so the cook is giving. The Object is cibum, so he is giving food. pictori is dative, so the artist is Indirectly Affected. The cook is giving food to the artist. (Similarly, in the final sentence, coquo is in the Dative Case.)
The cook gives food to the artist. The cook knows the artist to owe much money, and not (nec) to have this money. The cook gives many thanks to the artist.