Councils of Arimini and Seleucia, 359 AD

Councils of Arimini and Seleucia, 359 AD

Zlatomira Gerdzhikova


Institute for Balkan Stidies & Center of Thracology DOI
Bulgarian Academy of Sciences 25 June 2020
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Abstract: The article examines the parallel councils held in 359 in Arimini and Seleucia. At the council in Arimini, a symbol of faith was adopted, which will serve as a basis for organizing homoian Arians and distinguishing them from other heretical teachings derived from Arianism.

Keywords: Arianism, Arimini, Seleucia, Church Council, Heresy, Late Antiquity

In 358, Emperor Constantius II summoned two councils, which were held in parallel - the western bishops met in Arimini and the eastern in Seleucia. The purpose of the councils was to resolve the issue with the teachings of the Anomeanites (Soz. HE 3. 19, 4.16).

Although the councils were not held in the Balkans, the decisions of the council in Arimini will have a lasting impact on the course of the Arian conflict.

The main sources for the Arimini Council are: Hilarius Picatvius (Chron 2.36-45); Athanasius of Alexandria (Athan. De Synodis 8.1-8)

Athanasius wrote the main part of his text in the late autumn of 359, and later (probably at the end of 361) added as an appendix the letters exchanged between Constantius and the council and some passages in the text itself, which quoted the symbol of the council in Constantinople, as well as discussing the council held in Antioch in the spring of 360.[1]

The Council of Western Bishops met in July 359, with between 300 and 400 bishops present. Ursacius and Valens proposed the adoption of a new symbol of faith, which was signed at the council of Sirmium a little earlier that year. The symbol was developed by the bishops present in Sirmium, but was not presented or voted at the council itself.

Neither Constantius nor the bishops around him envisioned a council without heated debate. Probably because of this, the emperor sent special proxies to oversee the councils closely and to influence the decisions that would be made. The bishops present in Arimini were expected to compile and sign the document presented to them without discussing it, rather than preparing a new one. The document to be presented was prepared by Markus of Arethusa and supported by a small group of bishops, including Ursacius, Valens, Basil of Ancyra, Herminius of Sirmium, Egyptian Bishop George of Alexandria, and Pankrat of Pelusium, possibly Hypathian of Heraclea. On May 22, 359, in the presence of Constantius, the "Catholic symbol" was transmitted and signed (Athan. de Synodis 8.3-7).

The text of the symbol from Arimini has similarities to that from Antioch, and it is the first symbol to include Jesus' descent into hell. His main goal was to try to mediate and present a formula acceptable to both the Arians and the Nicaeans.[2] As terminology, probably borrowed from Acacius of Caesarea, it included technical terms and expounded Homoean Christology. This compromise did not satisfy anyone.[3]

Constantius sent letters to both councils, setting specific goals. The Eastern Council was instructed to resolve doctrinal issues first, then to consider the cases of individual bishops, such as Cyril of Jerusalem, who did not accept excommunication and exile and complained about bishops who committed violence in Egypt. The Western Council, under the strict supervision of the imperial envoys, received the same letter. Constantius sent a second letter asking the council of Arimini to focus on faith and unity and to send 10 envoys to inform him of what was happening. The emperor forbade them to make decisions about the affairs of the eastern bishops.

Flavius ​​Taurus, Praetorian Prefect of Italy and Africa from 355, was in charge of organizing the Western Council. He succeeded in securing a considerable presence of bishops. He sent envoys to Italy, Africa, Spain and Gaul with promises of free transport, provisions and invitations. More than 400 bishops came (Athan, de Synod, 8.1; according to Soz. HE IV.17.2 and Philost. HE IV.4.8 there were only 300).

The council began in July, and when the symbol was read, the bishops immediately split into two camps. Most bishops did not consider it necessary to adopt a new symbol after Nicaea. As a result, they reaffirmed the Nicene Creed, declared that nothing should be added or removed from it, and continued to prepare a formal condemnation of Arius and his heretical views (Moreover, they condemned Urasacius, Valens, Herminius, and Gaius (another bishop from Illyricus) for creating riots in the churches and attempting to change the Nicene Creed. The decisions were sent to Constantius in a letter requesting that the participants in the council be allowed to return to their cities. Taurus was instructed not to allow anyone to leave the city before decisions were made to satisfy the emperor (Sulpucius Severus, Chron, II.41.1, 43.3).[4]

Ursacius, Valens, and Germanius also arrived in Arimini. Together with their Western followers and probably a few dozen bishops from Illyricum, they formed a decent minority of 80 people. After seeing where things were going, they withdrew from the main church, where the council was being held in a smaller one nearby, and took action to thwart the decisions of the majority. They wrote a heartfelt letter to Constantius to allow them to return to their cities.[5]

Constantius left Sirmium in June and went to Constantinople, where he planned to spend the winter of 359/360. It is not clear when the two Arimini delegations met with him, but their treatment was different. Constantius welcomed the minority delegation but refused an audience with the others. Constantius left the capital and ordered the delegates to wait for him to return from Adrianopolis.

The delay and threats paid off. On October 10, in Nike, Thrace, Restimius of Caratagen withdrew the excommunication of Ursacius, Valens, Herminius, and Gaius, and signed the symbol that the other delegation (of the minority) had brought from Arimini. The creed they signed was a revision of the symbol of May 22, written by the Illyrian bishops, omitting the phrase "in everything" after "like Father" and forbidding the use of the phrase "one hypostasis" as well as "one ousia."[6] The place of signing the symbol was specially chosen, as the new symbol would sound like the Nicene Creed and could mislead some bishops (Socr. HE II.37.96, Soz. HE IV.19.8).[7]

The bishop of Ancyra, Basil, succeeded in convincing Constantius that it was necessary to summon a new council, which was best to be held in Nicomedia. In the autumn of 358, however, the city was shaken by an earthquake andtThe bishop of the city, Cercopius, died. (Soz. HE IV.16.1-13, Philost. HE IV.8-11). After lengthy discussions and possibly intrigue, Constantius decided to hold two councils in parallel - one in the East and one in the West. Barnes suggests that some of the closest to the emperor bishops, Ursacius, Valens, and Herminius, had suggested that the separation of the bishops would be in favor of ensuring the right decisions.[8]

While the meeting place of the Western bishops was determined immediately, the place and date of the meeting of the Eastern bishops was changed many times - in the autumn of 358 they were expected to meet in Ancyra, then the bishops were summoned to Nicaea in the early summer of 359., but the council was moved to Tarsus and was finally opened in Seleucia on September 27, 359 (Hilar. de Synod. 8; Soc. HE II.39.1-7; Soz. HE IV.16.14-22). Several bishops who feared excommunication, Basil of Ancyra, Macedonia of Constantinople, and Patrophilus deliberately delayed their arrival. Cyril, bishop of Jerusalem, and Eustathius, of Sebastia, also expected to settle the accumulated accusations.

On the very first day, the council split over what to start working on - to resolve the problems with the bishops described above and leave theological work for later, or to start religious disputes. George of Laodicea, Sophronius of Pompeiopolis, and Eleusis of Cyzick won the first vote to start the council by resolving theological disputes.

On the second day, the symbol adopted at the Council of Antioch in 341 was re-voted. The bishops, led by Basil, blocked the access of the group of Acacius and re-voted the symbol from Antioch. In the following days, some of the bishops, led by Basil, did not take part in the council and as a result Acacius proposed a new symbol in which the Son is similar to the Father. Anomoenism was condemned.

In the end, the council split and did not agree on theological disputes or accusations against some of the bishops.

Meanwhile, the council in Seleucia developed more rapidly. 160 bishops gathered at the council (Soc. HE II.29.5, Athan. De Synod. 12.1; according to Theod. HE II.26.9 the bishops were 150). The secular persons who supervised the council were Comes Leonas and Vasilidis Lauricius, duke of the province of Isauria. The council began on September 27, 359, with the presentation of the dogmatic views of the bishops, which provoked a dispute. First, they were asked to wait for the delayed bishops and then to discuss. Among those delayed were Basil of Ancyra, Macedonius of Constantinople, and Patrophilus of Scythopolis. The latter two announced that they were ill, most likely fearing that charges would be brought against them. Leontius refused to adjourn the meetings and some of the bishops refused to discuss anything until the charges against some of the bishops, such as Cyril of Jerusalem and Eustathius of Sebastia, were resolved. Others were of the opinion that doctrinal issues should be discussed first.

From the very beginning of the council, the bishops were divided into two factions. Acacius of Caesarea led one, along with Georigius of Alexandria, Uranius of Tyre, Eudoxius of Antioch, and 40 other bishops.

As a result, in 360 Constantius was forced to summon a council in Constantinople to discuss the decision of Arimini and to decide the division in Seleucia. The majority was led by George of Laodicea, Sophronius of Pompeopolis in Paphlagonia, and Eleusis of Cyzicus. The minority group wanted to adopt the Nicene Creed with as few corrections as possible, if possible, only by removing the term homoousios, while the larger group proposed writing a new symbol to replace the Nicene Creed.[9] After the debate, Akaki's party withdrew and the majority introduced the symbol of 341, read it and voted. The next day they met at the main church in Seleucia, behind closed doors, and signed the symbol.

Acacius and his followers appealed the incident, claiming that the procedure was illegal after it was held behind closed doors. Acacius has prepared his own version of a symbol, which he read to Leotnas and Lavricius. On September 29, Leonas tried to convene the council again. Macedonius and Basil arrived this time, but the Acacian party refused to sit with them, arguing that the two bishops had already been excommunicated and were currently accused and should be excluded from the discussion. The latter agreed and after their withdrawal Leonas announced that he had a declaration from Acacius. It turned out to be a symbol of faith (the full text is preserved in Epiph. Pan. 73.2515, in partial quoted by Athan. De Synod. 29.2-9, Soc. HE II.40.8-17). Since the terms homoousios and homoiousios were very troubling, while the term anomoios was introduced very recently, they rejected the terms homoousios and homoiousios as contradictory to Scripture and anathemasal anomoios. Instead, they acknowledged that the Son was like the Father and presented a symbol of honor identical to that written in the Sirmium in May, and excommunicated all who disagreed with him. Acacius and his followers signed the symbol, but Sophronius protested and ended the third day without a specific decision.

The debate continued on the fourth day. Eleusis of Cyzicus repeated that the symbol of 341 is sufficient, and Acacius was forced to specify how the Son is like the Father. When he states that this is only by nature and not in essence, it becomes clear that the majority does not agree. Over time, the discussion became more intense and Leonas ended the session. The next day he refused to join the bishops, which was well received by Acacius, but not from the majority of bishops. They began to discuss the case of Cyril of Jerusalem, as instructed by the emperor in his letter. Cyril was in Seleucia and expected to be heard. The majority invited Acacius, as the bishop presiding over the council, who excommunicated Cyril, as well as supporters of the bishop of Caesarea, which included people accused of theological transgressions. When they did not appear, despite repeated invitations, the bishops excommunicated Acacius, George of Alexandria, Uranus of Tire, Theodulus of Keretapa in Phrygia, Theodosius of Philadelphia in Libya, Evagrius of Mytilene, Leontius of Tripoli, Eudosius of Antioch, and Patrophilus of Skito. Banished 9 more bishops from communion until they provided information in order to be acquitted of the charges against them. (Athan. De Synod, 12.5, Socr. HE II.40.43-45). Anian was then nominated as Eudoxia's deputy in Antioch. Acacian party took revenge by handing him over to Leonas and Lauricus, who excommunicated him. After persuading the emperor's representatives to sign the excommunication of Anian, they finally sent envoys to Constantinople (Soz. HE IV.23.1).

Acacian delegation arrived first at the emperor's. Constantius was irritated by the refusal of the Eastern bishops to accept the Homoean symbol and abolished the remission of curial duties and other civil duties enjoyed by some bishops (Socr. HE II.41.1-4, Soz. HE IV.23.1). The emperor's refusal was motivated by what he said was the impending capitulation of the Western bishops in Arimini. Arimini's envoys returned shortly after the symbol was signed by Nike, but Taurus and Bishops Ursakius and Valens applied constant pressure and soon forced the last resisting bishops to sign the new symbol. A second delegation was sent to the emperor to inform him that the Western bishops were already united in accepting the new symbol. They arrived in Constantinople at the end of the year (Sulpicius Severus, Chron. II.44.1 traces that the final capitulation took place no earlier than January 360).

The pressure on the envoys from Seleucia had a similar result. They presented the possibility that only the adoption of the Homoean symbol would provide a barrier against the obvious heresy of Aetius (Sulpicius Severus, Chron. 2.45.1, Theod. HE II.27.7-12, Soz. HE IV.23.1-7). When the embassy arrived in Arimini, Acacian party presented itself as a bulwark at the Council of Seleucia and warned Westerners of the danger of Aetius.

On December 31, 359, both councils signed the symbol that marked the beginning of a new Homoean Orthodoxy (Soz. HE IV.23.8).

Athanasius wrote his text on the councils as soon as he learned what had happened in Seleucia, but before he learned of Constantius' reaction. The bishop wrote his letter for a purely practical purpose - to find allies in the face of homoeousians from Asia Minor. His work hardly received an immediate response, but the important thing in this case is that Athanasius turned for an alliance to the bishops, who in 351 excommunicated him and who he had shortly denouncing that they were Arians and used ominous language.[10]


[1] Barnes 1993, 133.

[2] Kelly, 1972, 290.

[3] Barnes, 1993, 144.

[4] Barnes, 1993, 145.

[5] Barnes, 1993, 145.

[6] Kelly, 1972, 291.

[7] Barnes, 1993, 146.

[8] Barnes, 1993, 140.

[9] Barnes, 1993, 146.

[10] Barnes, 1993, 133.



Athanasius of Alexandria

Athanasius, De synodis Arimini et Seleuciae. H. G. Opitz (ed.) (1935–41) Athanasius: Werke II.1, Berlin, 231–78.

A. Robertson (ed.), St. Athanasius: Select Works and Letters, Select Library of Nicene and Post-Nicene Fathers, Second Series, vol. 4, (Oxford, 1892) 451–80.

Epiphanius, Panariaon Epiphanius, GCS, 3 vols, rev. by J. Dummer, C.-F. Collatz and M. Bergermann.

       Frank Williams (tr.) The Panariaon of Epiphanius of Salamis, Books II and III (Sects 47-80, De Fide) (Brill, 1994).

Hilarius Pictaviensis, Tractatus mysteriorum, Collectanea antiariana, Ad Constantium imperatorem, Hymni, Fragmenta. Pseudo-Hilarius, Epistula ad Abram filiam, Hymni – ed. A. Feder 1916, CSEL 65 Hilary of Poitiers, De Synodis (On the Councils) J.-P. Migne (ed.) (1845) Sancti Hilarii Pictaviensis Episcopi Opera Omnia: Tomus II, Patrologia Latina 10, Paris, 479–546.

Philostorgius, Historia Ecclesiastica, J. Bidez (ed.) (1981) Philostorgius: Kirchengeschichte, GCS, 3rd edn, rev. by F. Winkelmann.

P. R. Amidon (tr.) Philostorgius: Church History (Atlanta, Georgia, 2007)

Sokrates Scholasticus, Historia ecclesiastica, Günther Christian Hansen (ed.), GCS N.F. 1 (Berlin, 1995).

Sozomenos, Historia ecclesiastica, Joseph Bidez and Günther Christian Hansen (eds), GCS 50 (Berlin, 1960);

Ernst Walford (tr.), The ecclesiastical history of Sozomen, comprising a history of the church form A.D. 324 to A.D. 440 (London, 1855).

Sulpicius Severus, Chronica. G. de Senneville-Grave (ed.) (1999)

P. Schaff and H. Wace (edd.) (Sulpitius Severus, Vincent of Lerins, John Cassian, Select Library of Nicene and Post-Nicene Fathers, Second Series, vol. 11, (Oxford, 1894), 71–122.

Theodoret, Historia ecclesiastica, Léon Parmentier and Günther Christian Hansen (eds), Theodoret Kirchengeschichte, GCS N. F. 5, (3rd edn, Berlin, 1998);

Blomfield Jackson (tr.), ‘The Ecclesiastical history, dialogues, and letters of Theodoret’, in Henry Wace and Philip Schaff (eds), Theodoret, Jerome, Gennadius, Rufinus: Historical Writings, NPNF 3 (Oxford 1892, repr. 1995), 33–160.

Secondary Sources

Barnes, T.D. (1993) Athanasius and Constantius: Theology and Politics in the Constantinian Empire (Cambridge, MA and London: Harvard University Press).

Kelly, J.N.D. (1972) Early Christian Creeds (London: Longman)


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