SEPARATION OF CHURCH AND STATE: THE BEGINNING

The Concordat of Worms (1122 AD) is the first major agreement in the West setting the boundary lines of Church and State.  From the Encyclopedia Britannica:

[A] compromise arranged in 1122 between Pope Calixtus II (1119–24) and the Holy Roman emperor Henry V (reigned 1106–25) settling the Investiture Controversy, a struggle between the empire and the papacy over the control of church offices. It had arisen between Emperor Henry IV (1056–1106) and Pope Gregory VII (1073–85). The concordat marked the end of the first phase of the conflict between these two powers. A similar conflict, between the papacy and the king of England, had been composed in 1107; that settlement provided the basis for the Concordat of Worms, which made a clear distinction between the spiritual side of a prelate’s office and his position as a landed magnate and vassal of the crown. Bishops and abbots were to be chosen by the clergy, but the emperor was authorized to decide contested elections. The man chosen was first to be invested with the regalia, or powers, privileges, and lands pertaining to his office as vassal, for which he did homage to the emperor, and then with the spiritualia, or ecclesiastical powers and lands, symbolized by the staff and ring, which he acquired by his consecration and from his ecclesiastical superior, who represented the authority of the church