In ancient Greek mythology, the legend of Gemini constellation - "Castor and Pollux are two brothers who love each other, but the former has all their lives, while the latter enjoys immortality. After Castor's death, Pollux begged his father Zeus to revive him, even at the cost of giving up his immortality. Zeus was greatly moved, so he arranged for the two brothers to take turns to live in the earth and the underworld, alternating daily. In this way, brothers divide immortality and death equally.