Jupiter was the Roman counterpart of Zeus, the supreme god and father. He was a god of the sky and his name is derived from Indo-European roots dyaus/pitr, which literally mean god/father. In Latin the common oath "by Jupiter" would be rendered "pro Jove" (Jove being a different form of his name). In the Christian tradition there is no religious significance to this exclamation but English writers, by using it as an expression of surprise or pleasure, avoided taking God's name in vain; thus "by Jupiter" or "by Jove" was used to replace the offensive "By God." To describe someone or something as jovian means that one partakes of that awe-inspiring majesty that is particular to a supreme god. Many mythological names also found a new existence in the field of astrology. Since it was felt that the heavenly bodies influence the life of humans on earth, celestial bodies were given appellations drawn from mythology, for example Jupiter became the name not only of a god but a planet. Those who were born under the influence of the planet Jupiter were said to be of a cheerful disposition, hence the meaning of the adjective, jovial.