"so long as nobody knew its name"

Public DomainRumplestiltskin
In myth and legend, knowing something or someone’s name gives you power over them. A good example of this is the well-known Western fairy tale “Rumplestiltskin”. In it, the dwarf named Rumplestiltskin helps a young lady whose father lied that she could spin gold. The king gave her three nights to spin gold, otherwise she would be executed. Rumplestiltskin helps her in return for her promise to give him her first-born child. When her child came, she tried to convince him to leave her child with her. He gives in, but only if she can guess his name.