The Charmed Ones are a set of three sisters prophesied to be the most powerful good witches the world has ever known. Their arrival was foreseen by Melinda Warren, the founder of the Warren line of witches and their ancestor. They have access to the Power of Three, the strongest force of magic.
The original Charmed Ones were Prue, Piper and Phoebe Halliwell. Each inherited one of Melinda's three magical powers, to move objects with the mind, to stop time and to see the future. However, after the death of Prue, a fourth sister was revealed. Paige Matthews then took the place of her eldest sister and reconstituted the Charmed Ones.