Ayres (117-132), Behr (77-83).
A group of Eastern bishops, including Eusebius N., (now Constantinople), Acacius of Caesarea, Asterius, and the Emperor Constantius, met at this council, and produced a number of documents (extant in Athanasius' De Synodis):
The first denies being Arian – a reaction to Julius' letter, and Athanasius' polemical strategy.
The second is the Dedication Creed. It is clearly anti-Sabellian, and anti-Marcellan. It also contains anti-Arian anathemas. Ayres thinks the creed shows that the East is broadly 'Eusebian'. Athanasius treats it as 'Arian', but Hilary of Poitiers is prepared to treat it as broadly pro-Nicene in its anti-modalist intent. The text notably lacks any mention of the Son being of the Father's ousia. Behr notes that it emphasises the Son's and Spirit's independent and external existence, and the Son's relation as image of God, as well as speaking of three hypostases, one in agreement. Behr describes it as one of the last attempts of a clear statement of the 'pluralist eikon theology' before it dispersed along divergent lines.
The third text is a personal statement of belief from Theophronius.
The fourth text, which I will refer to as the 4th Antiochene Creed, is a shorter statement, prepared to be sent West to Constans, lacking either ousia or image language, and explicitly anti-Marcellan in its eschatology.
Amidst tensions between Constans and Constantius, a council was scheduled for Serdica in 343, with both Eastern and Western delegations. Yet the two groups never met, the Westerns insisting on Athanasius and Marcellus' presence, and the Easterns refusing the idea totally. The Easterns retreated to Philippopolis, and issuing their decrees from their, including a reworked version of the 4th Antiochene and fresh condemnations of Athanasius and Marcellus. For the part of the Westerns, they denounced the position of Ursacius and Valens, and issued their own long statement of faith. The Athanasian emphases on the continuity of being of Father and Son is pitted against the Eusebian image-theology and clear distinction.
A further council was held, issuing the Macrostich creed, known for its long-verse structure. It is essentially another reworking of the 4th Antiochene, avoiding ousia language, emphasising Father-Son continuity, and maintaining an anti-Marcellan thrust. The Son is 'like in all things' – a shift towards 'Homoian' theology that will become increasingly indefinite about exactly what likeness the Son has to the Father (a shift that will lead to the emergence of radical Homoians, Heterousians like Aetius and Eunomius, which will eventually send the Homoiousians back into the arms of Nicaea). It also asserts that the Son must be begotten by choice or will, not necessity, which is a very non-Athanasian position that shows the ascendancy of the 'Arian' dichotomies (as Athanasius sees it).
The Macrostich creed was brought West to a council in Milan, but failed to be presented, as the Western bishops insisted the Easterns denounce Arius and his theology before doing any business. Naturally, the Easterns were offended by the suggestion, and refused to do any such thing. Nonetheless, the council condemns Photinus, a vocal exponent and developer of Marcellus' theology, and Marcellus' position in the West becomes increasingly compromised.
The Return of Athanasius
June 345 Athanasius is granted permission by Constantius to return to Alexandria, whither he arrives Oct 21, 346 and remains until 356, his longest stay in his see.