Sandmann was The Moon’s first spirit created, technically his son, who made and controled both dreams and nightmares since the beggining. Gold used to be a horse breeder and sailor back then, on one of his voyages after offering horses to Poseidon things didn’t turned as how should have and he was cast into the waters for his offences to the God, The Moon granted him a second chance as spirit and was when he met Sandmann, they started a teacher and apprentice relationship before falling in love, but time still was passing while on that, and the new era was at the corner, Sandmann grew worried of people forgetting spirits more every passing day, so he used his powers to make sure they would remember, The Moon and Sandmann fighted about it and it end up in The Moon sinking him in the ocean and taking away his powers, but since Sandmann never was a human in first stance, he didn’t lost all his powers and fell asleep at the bottom of the ocean, The Moon gave his rank to Gold, who understood the situacion and that humans needed dreams, but was regretful and missed Sandmann, so he sang to the ocean until the day he would come back