Given a sentence and two mentions from the text (arguments), indicate a phrase (a verb or noun phrase) that describes the relationship between the provided arguments.

Sentence: 'Calydon was a southern city of Aetolia , founded by Calydon , son of Aetolus and brother of Pleuron .', Argument/Subject 1: 'calydon', Argument/Subject 2: 'aetolium'
be city in