Final answer:
The principle of apostolic succession is the belief that the authority of the Apostles, bestowed by Jesus, is passed down through an unbroken line of bishops, culminating in the pope's supreme authority over the Christian Church.
Step-by-step explanation:
The principle of apostolic succession refers to the belief in Christianity, primarily within the Catholic Church, that authority is passed down through a continuous line of bishops starting from the Apostles and Jesus Christ himself. This doctrine posits that the pope and bishops, as successors of the original Apostles, maintain the same teachings and governing authority given by Jesus to His first disciples. The Bishop of Rome, the pope, claims this succession from the Apostle Peter, who is believed to have been granted the 'keys to heaven' by Jesus, thus establishing the Petrine succession, which in turn signifies the pope's role as the supreme authority in matters of faith and church governance.
By the mid-fifth century CE, the popes had begun to assert full authority over other bishops, creating a hierarchical structure within the church. This belief implies that only bishops can legitimately appoint church leaders, and such consecrations and ordinations differentiate the clergy from lay Christians, despite arguments like those from Martin Luther that all baptized Christians share in a common priesthood. The investiture controversy of the 11th century and subsequent events further illustrate the evolution and cementation of this doctrine, as popes began to exercise stronger control over church appointments, challenging secular authorities and enhancing the distinction between spiritual and temporal power.