Bloom's father Rudolph apparently named his dog "Athos" after the character in Alexandre Dumas' The Three Musketeers, but there also seems to be an echo of Odysseus' dog, who has the very similar name of Argos. Argos perks up and then dies after seeing Odysseus, who left for Troy 19 years earlier. Bloom thinks in Hades that Athos too "took it to heart, pined away" when his master died.

John Hunt 2014

The reunion of Odysseus (disguised as a beggar) and Argos, by an unknown artist. Source: