Calydonian Boar
In disjointed episodes that have survived, Pirithous had heard rumors about Theseus' courage and strength in battle but he wanted proof. He rustled Theseus' herd of cattle from Marathon, and Theseus set out to pursue him. Pirithous took up arms and the pair met, then became so impressed by each other they took an oath of friendship. They were among the company of heroes that hunted the Calydonian Boar, another mythic theme that was already well known to Homer's listeners.