«SEMPITERNUS REX». - Encyclical of Pius XII for the XV centenary of the Ecumenical Council of Chalcedon (8 Sept. 1951).
The Council of Chalcedon is the third of the great Christological Councils, after that of Nicaea (commemorated in the Holy Year 1925) and that of Ephesus (encycl. Lux Veritatis, 25 Dec. 1931), which defined respectively the consubstantiality of the Son with the Father and the unity of person in Christ. After this brief reminder the encyclical recalls the historical circumstances and the theological climate in which the Council of Chalcedon took place, highlighting the request made by the Eastern bishops and the acceptance of the intervention of Pope St Leo the Great. Within the framework of
this important solemn assertion of the primacy of the Roman Pontiff, Canon 28 is presented in its true value; although it does not, according to the intentions of its authors, contain a true denial of the primacy, it was rejected by the Pope and then by the Emperor and even by the Bishop of Constantinople himself, who judged it devoid of value because it was drawn up in the absence of the papal legates. In the second part of the encyclical the meaning of the dogmatic formula of Chalcedon is illustrated, with a warning against errors that are still rife today and which compromise the unity of person in Christ. The Supreme Pontiff does not intend merely to speak of the kenotic theory widespread among non-Catholics, but also refers to certain currents within Catholic theology itself.
The distinguished document concludes with an appeal to dissident Orientals to return to the unity of the sheepfold and to union with the Apostolic See, whose primacy was so excellently acknowledged by their fathers at the Ecumenical Council of Chalcedon (AAS, 43 [1951], pp. 625-44).