From the beginning of Christian history, the assertion of Christ's lordship over the world and over history has implicitly recognized that man should not submit his personal freedom in an absolute manner to any earthly power, but only to God the Father and the Lord Jesus Christ: Caesar is not "the Lord". "The Church. . . Believes that the key, the centre and the purpose of the whole of man's history is to be found in its Lord and Master."
Source: Catechism of the Catholic Church (Vatican.va)