Argos, Odysseus’s dog in the works of Homer. After 20 years of waiting for Odysseus to return home, the dog is the only one to recognize him, he wags his tail and Odysseus sheds a tear, and Argos dies after meeting him one last time. 

Argos was whelped and trained to be the finest hunting dog of his Lord’s estate, and just before he was old enough to go hunting with Odysseus, our hero left on his journey, only returning when Argos was too old to do aught but lift his head in recognition of his master.