Castor and Pollux by Clovis Medeiros, 2012.
This day is sacred to the Dioscuri in Ancient Rome, though they were venerated by the Greeks as well as the Romans.
Twins born to Leda, Queen of Sparta, Castor was the son of Tyndareus, king of Sparta, but Polydeuces (Pollux to the Romans) was the son of Zeus. They were inseparable companions in life, and continue to be so after death, as well. When Castor died, Polydeuces shared his immortality with him, so they alternate days among the dead in the Underworld, and living on Olympus with the gods.
They are helpers of humanity, especially travellers and mariners.