Pope Stephen III
The word "cardinal" is derived from the Latin "cardō", meaning "hinge". The office of cardinal as it is known today slowly evolved during the first millennium from the clergy of Rome. "The first time that the term "cardinal" appears in the "Liber Pontificalis" is in the biography of Pope Stephen III (IV) when in the Roman Synod of 769, it was decided that the Roman pontiff should be elected from among the deacons and cardinal priests."