Concerning the Canons of the holy Fathers and regional Councils
"The holy and Ecumenical Fourth Council was held in Chalcedon, an important city in Bithynia, during the reign of Emperor Marcianus and Pulcheria in the year 451 after Christ. The number of Fathers attending it was 680..." (Rudder, p. 241)
Fresco of the Holy and Ecumenical Fourth Council. Virgin Nativity Cathedral of the St. Ferapont Monastery, Belozersk, by Dionisy in1502.
We pronounce it just and right that the Canons promulgated by the Holy Fathers, in each and every Council down to the present time, continue in full force and effect. (Rudder, p. 245)