Nicaea, First Council of, 325, 1st ecumenical council, convened by Roman Emperor Constantine the Great to solve the problems raised by Arianism. It has been said that 318 persons attended, but a more likely number is 225, including every Eastern bishop of importance, four Western bishops (among them Hosius of Córdoba, president of the council), and two papal legates. The chief figures at the council were Arius and his opponent, Athanasius. The council adopted, as a test of faith, a formula that seems to have been based on a simple baptismal creed presented possibly by Eusebius of Caesarea; this was not, however, the creed generally circulated today as the Nicene Creed (see creed). The formula included the Greek word homoousion [consubstantial], which was used concerning the Son and the Father. The word, suggested probably by Hosius, became the touchstone of orthodoxy and the bugbear of Arianism, for it established the divinity and the equality of the Son to the Father. The creed was accepted by all the bishops except two, who were banished along with Arius to Illyricum. The council ruled on other questions as well, attempting to standardize the date of Easter and granting patriarchal authority to the bishop of Alexandria. The First Council of Nicaea was significant as the model and the original of great councils. The test it adopted provided a universal statement of faith in place of the earlier and varying baptismal formulas.