The First Ecumenical Council of Nicaea in 325 is perhaps best known for addressing and condemning the Arian heresy which claims that Jesus was not divine. Yet, this Council, celebrating its 1,700 anniversary, is also important for two other and related reasons: it defined the shape and practice of the liturgy for the Church, East and West, for all time, and, by clarifying the reality of Jesus’ divinity, Nicaea provided the theological bedrock on which the liturgy would be established. In a way, these were the more decisive results of Nicaea than the fate of the Arian heresy. For the Council itself, while authoritatively repudiating the Arian heresy, did not end it. Neither did the supposedly violent death, 11 years later, of Arius himself.¹ Instead, the heresy stormed on while it was countered by orthodox councils and saints of those centuries, though the faithful were often small in number.

St. Basil of Caesarea describes the aftermath of the Council in terms of a naval battle: “See the rival fleets rushing in dread array to the attack. With a burst of uncontrollable fury they engage and fight it out.”² He goes on to explain his analogy showing how, after Nicaea, there were even more heresies and struggles surfacing after the example of the Arians: “But when the attitude of our foes against us was changed from one of long standing and bitter strife to one of open warfare, then, as is well known, the war was split up in more ways than I can tell into many subdivisions, so that all men were stirred to a state of inveterate hatred alike by common party spirit and individual suspicion.”³ The decades after the Council, even up to the Council of Constantinople in 381, were wrought with theological strife throughout the Church.

Even still, what Nicaea did succeed to accomplish was essential for the Christian faith, for it defended one of the most foundational Christian truths: Jesus Christ is the divine Son of the Father, “not created” (ou poiethenta), and “of the same substance of the Father” (homoousion to Patri). This may seem to be a pedestrian proclamation from our perspective after 1,700 years of dogmatic Christological precision. However, in the fourth century, there was nothing more crucial being discussed than the divinity of Jesus Christ.⁴ Rightly so, for upon this single truth rests the salvation of humanity, our sanctification and divinization, and the entire possibility of Christian liturgy.

It is this last theme that this article will spend time considering, i.e., the consequences of Nicaea for the practice and nature of the liturgy. However, due to the early timing of the Council, there isn’t sufficient historical evidence for euchological comparisons of liturgical prayer before and after 325, or even across most of the fourth century.⁵ This is because, on the one hand, the practice of the liturgy in this time was not fully based on liturgical texts or missals like today,⁶ and, on the other hand, extant texts that reference the liturgy from this time are secondary accounts—like homilies or “church orders”—which describe the liturgy externally and only give partial references to prayers used at the time.⁷ Therefore, measuring the immediate effects of Nicaea on the liturgy is quite limited to the authentic texts of the Council, its declaration, 20 canons, and an accompanying letter to the Church of Alexandria.

In light of these historical limitations, two paths help to identify the liturgical significances of the Council. The first is to examine the canons, briefly considering their content and effects. The second is to unlock the liturgical significance in the Council’s dogmatic declaration: the divine nature of Jesus Christ.

Liturgical Canons of Nicaea

To respond to ecclesial problems of the day—such as ill practices among the clergy, lapsed Christians, and heretical sects—the Fathers at Nicaea promulgated a new Creed of orthodox belief and 20 juridical “canons.” At a broader level, such an authoritative pronouncement presumes very practical consequences for the liturgy in the centuries that follow, for it set the precedence for the following councils to regulate and standardize practices in the Church.⁸ Nonetheless, the canons demonstrate the principle of subsidiarity regarding the different traditions and practices of the diverse provinces, or patriarchates. For example, Canon 6 gives certain patriarchates local jurisdiction and certain privileges, “since the like is customary for the Bishop of Rome also.”⁹ Thus, there is a reverence for each particular Church, her authority, and her practices, which eventually allowed for the continued development of distinct liturgical families. Nicaea governed universally in response to certain greater disputes such as orthodox belief in Jesus’ divinity, on the one hand, but, on the other hand, it allowed for local hierarchical authorities to govern accordingly.

At the narrower level, certain canons address very specific matters: for example, the moral behavior of clerics. In this regard, two canons seek to rein in the opposite extremes against chaste celibate living: Canon 1 forbids the practice of self-castration and Canon 3 prevents clerics from cohabitating with women to whom they are not related. Liturgical canons specify the proper preparation for initiation and orders (Canons 2 and 9), questions concerning the validity of the sacraments of heretics (Canons 8 and 19), the restoration of the lapsed through penance (Canons 10, 11, and 14), communion to the dying (Canon 12), proper hierarchy and postures during liturgical celebrations (Canons 18 and 20), and the date of Easter (the synodal letter). Such laws helped encourage the gradual standardization of liturgical life in the Church through subsequent centuries and councils.

Besides the above legislations, the composition of the Nicene Creed also bears evident liturgical influence, manifest today in the weekly recitation of the Nicene-Constantinopolitan Creed. Nonetheless, this creed wasn’t immediately a liturgical reality at all. Indeed, Eastern Churches brought the developed creed into the Divine Liturgy within a few centuries after the Council of Constantinople,¹⁰ but Latin Churches did not see its use during the Mass until later and not in Rome until the 11th century.¹¹ These above consequences are influential at a broader level, but they prove to be more at the surface in comparison to the declaration which rests at the heart of the Council: Jesus’ divine nature.

Nature of the Son: Arius and Nicaea

The composition of the Nicene Creed and its accompanying anathema against the Arian heresy reveal the most significant, but easily overlooked, consequence of the Council of Nicaea for the liturgical life of the Church. In the end, there is one essential truth implicitly defended by the Council’s declarations: without a proper Christology, there can be no Christian liturgy. To deny the divinity of the Son of God is to deny the very nature of the liturgy. Pondering Arius’s theology, Nicaea’s response, and the theology of the Church Fathers, with St. Thomas Aquinas, demonstrates this actuality.

After his condemnation as a heretic and the destruction of his writings, St. Athanasius’s text Against the Arians is the only access we have to Arius’s thought, in which he reports some of Arius’s Thalia to combat his teaching. According to St. Athanasius, Arius sought to fight the tendency of viewing any multiplicity in God, claiming that he is only One, to the exclusion of the Son and Spirit: “He alone has no equal, no one similar, and no one of the same glory [homodoxon]. We call him unbegotten, in contrast to him who by nature is begotten. We praise [anumnoumen] him as without beginning in contrast to him who has a beginning. We worship [sebomen] him as timeless, in contrast to him who in time has come to exist.”¹²

Already here, one can foresee effects of such a theology on worship, i.e., Jesus is neither praised nor worshiped in the manner of the Father. Rather, Arius held Jesus to be a created being: “He who is without beginning made the Son a beginning of created things. He produced [technopoiesas] him as a son for himself by begetting him. He [the Son] has none of the distinct characteristics of God’s own being for he is not equal to, nor is he of the same being [homoousios] as him.”¹³ Denying the sameness of being between the Father and the Son, Arius conflates Jesus’ nature as “begotten” (geneton) with being “created” (technopoiesas). This brings Arius to the point of saying, “There was [a time] when the Son was not,” and “The Son was not before he was begotten.”¹⁴

The Council of Nicaea replied with a precise correction, declaring Jesus to be “of the substance of the Father,” and “begotten, not made [ou poiethenta], being of one substance with the Father [homoousion to Patri].” It concluded with an unmistakably aimed condemnation: “Those who say: There was a time when He was not, and He was not before He was begotten; and that He was made out of nothing; or who maintain that He is of another hypostasis or another substance, or that the Son of God is created, or mutable, or subject to change, the Catholic Church anathematizes.”¹⁵ Against the Arians, the Church proclaims the ever-present truth of Jesus’ nature: The Son of God is begotten, though not created; he is co-eternal, divine, and of the same being of the Father. As the Church Fathers and St. Thomas Aquinas teach, this union of true divinity and true humanity is the necessary foundation for Christian worship in the New Covenant. Indeed, to cut the Son from the being of God is to undermine the possibility of salvific liturgy.

Liturgical Significance of the Son’s Divinity

At the end of the Eucharistic prayer in the Roman Rite, the priest elevates the Sacred Body and Blood and proclaims, “Through him, and with him, and in him, O God, almighty Father, in the unity of the Holy Spirit, all glory and honor is yours, for ever and ever.”¹⁶ It is through, with, and in Jesus Christ that the each of the faithful in the Church can offer right worship to the Father. Yet, does this necessarily mean that Jesus needs to be divine? Could not the Father have promulgated his worship so that Jesus, a “created” mediator, could still be the bridge between man and God? Following Fathers of the Church and St. Thomas Aquinas, the answer is a clear and emphatic “No.” The Incarnation of the Son of God, precisely as true God and true man, is at the center of his salvific mediation and the liturgy.

St. Thomas identifies both the High Priesthood and the Mediatorship of Jesus in his human nature, and not his divine nature,¹⁷ for “Christ alone is the perfect Mediator of God and men, inasmuch as, by His death, He reconciled the human race to God.”¹⁸ However, this does not mean that someone who is man alone, such as Moses, could have been the “one mediator between God and men” (1 Timothy 2:5). Due to the unique union of the divine nature and the human nature in Jesus, what is said of one nature can be said of the whole Person. Further, the union of the natures also work together towards the purpose of the Incarnation; thus, the will of his Godhead has his human nature, body and soul, subject to it.¹⁹ It is in the union of Jesus’ “priestly” and “mediating” humanity with his Divine Person in one hypostasis that forms the bedrock of the liturgy of the New Covenant. The perfect offering of Jesus the High Priest both blotted out sin by grace and removed the debt of punishment by satisfaction.

Already in the second century, Irenaeus of Lyon (c. 130-202 AD) described this truth in Adversus Haeresaeus, saying, “For unless man had overcome the enemy of man, the enemy would not have been legitimately vanquished. And again: unless it had been God who had freely given salvation, we could never have possessed it securely. And unless man had been joined to God, he could never have become a partaker of incorruptibility. For it was incumbent upon the Mediator between God and men, by His relationship to both, to bring both to friendship and concord, and present man to God, while He revealed God to man.”²⁰ St. Irenaeus describes the means and effects of what liturgical worship of God in the Church brings about. By means of participation in the God-man, we have access to the effects of salvation and incorruptibility, which could only be won by God himself and won for humanity by a human.

Origen (c. 185-253), commenting on the sacrifice of Isaac by Abraham, notes how Jesus, in his “flesh,” i.e., his human nature, undergoes suffering and death, while at the same time “the Word kept his impassability” which is proper to Jesus’ divine nature. He concludes, “Thus he is victim and pontiff according to the spirit because he who offers the victim to the Father according to the flesh, is he himself offered on the altar of the cross.”²¹ Jesus’ human and divine natures working in union bring about the one true and efficacious sacrifice to the glory of the Father.

Safeguarding the truth of Jesus’ divinity, the Council of Nicaea ensured the possibility of participating in the salvation, divinization, and liturgical glorification that Jesus opened up for his Church. In recognition of this, when commemorating the Incarnation of the Son of God at Christmas, the Church prays with strength against Arianism and the heresies of the fourth century by emphasizing the true nature of Jesus Christ and his most “marvelous exchange”²² with mankind:

_{For through him the holy exchange that restores
our life has shone forth today in splendor:
when our frailty is assumed by your Word
not only does human mortality receive unending honor
but by this wondrous union we, too, are made eternal.}²³

1. The fifth-century historian Socrates of Constantinople recounts the unpleasant death of Arius in Constantinople where, while seeking a place for digestive relief, Arius’s internal organs suddenly became his external organs.
2. St. Basil, De Spiritu Sancto, no. 76 (translated by Blomfield Jackson, in Nicene and Post-Nicene Fathers, Second Series, Vol. 8, Philip Schaff and Henry Wace (eds) (Buffalo, NY: Christian Literature Publishing Co., 1895).
3. St. Basil, De Spiritu Sancto, no. 77.
4. Even “barbers offered opinions on the origins of the Son…” (Cf. David Brakke, Athanasius and the Politics of Asceticism (Oxford: Clarendon Press, 1995), 57–59).
5. “…while we have materials that can be used to demonstrate the interrelationship between pro-Nicene theologies and their liturgical practice…, we have little that can be dated with sufficient certitude to show developments over the course of the fourth century,” Lewis Ayres, “Nicaea and Its Legacy: An Introduction,” The Harvard Theological Review, 100/2 (2007), 141–44; cf. also Daniel Galadza, “The Liturgical Reception and Commemoration of the First Council of Nicaea,” Eastern Theological Journal 8/2 (2022) 181–217.
6. Cf. Cassian Folsom, The Liturgical Books of the Roman Rite. A guide to the study of their typology and history. Volume 1: Books for the Mass (Naples: EDI, 2023), “Chapter One. From structured improvisation to fixed formulas,” 25–32.
7. Consider St. Ambrose of Milan’s comparison of the Ambrosian liturgical tradition to that of Rome in which he quotes significant portions of the Roman Canon as it would have been known in the third and fourth centuries (cf. St. Ambrose, De Sacramentiis, V–VI).
8. “Thus, the only references to the Council of Nicaea in liturgical scholarship are to the aftereffects of the condemnation of Arianism… and the ‘general process of assimilation and liturgical standardization that is characteristic of orthodox Christianity after the Council of Nicaea in 325,’” Daniel Galadza, “The Liturgical Reception…,” 187.
9. The Council of Nicaea, Canon 6.
10. The Patriarch Timothy of Constantinople (from 511 to 518) is accredited with introducing the Nicene-Constantinopolitan Creed into the daily Divine Liturgy (cf. Paul L. Gavrilyuk, “The Legacy of the Council of Nicaea in the Orthodox Tradition,” in Young Richard Kim (ed), The Cambridge Companion to the Council of Nicaea (Cambridge: Cambridge University Press, 2020), 335-336).
11. “…we know that it entered first into the Papal Mass when Emperor Henry II, in 1014, came to Rome, marveled that the Creed was not recited, and thus put pressure on Pope Benedict VIII to introduce it, and he was satisfied,” Antonio Miralles, Teologia Liturgica dei Sacramenti. I. Eucaristica (Roma: EDUSC, 2022), 101 (my translation).
12. St. Athanasius, De Synodis, no. 15 (translated by A. West and G. Thompson).
13. St. Athanasius, De Synodis, no. 15 (trans A. West and G. Thompson).
14. St. Athanaius, Against the Arians, Discourse 1, Chapter 4, no. 13 (trans A. West and G. Thompson).
15. Henry Leclercq, “The First Council of Nicaea,” in The Catholic Encyclopedia (New York: Robert Appleton Company, 1991).
16. The Roman Missal: Renewed by Decree of the Most Holy Second Ecumenical Council of the Vatican, Promulgated by Authority of Pope Paul VI and Revised at the Direction of Pope John Paul II, Third Typical Edition. (Washington D.C.: United States Conference of Catholic Bishops, 2011), Order of Mass, no. 98.
17. “Christ, as God, is in all things equal to the Father. But even in the human nature He is above all men. Therefore, as man, He can be Mediator, but not as God” (STh., III q.26 a.2 ad 2). “Although Christ was a priest, not as God, but as man, yet one and the same was both priest and God” (Saint Thomas Aquinas, Summa Theologiae, ed. The Aquinas Institute, trans. Laurence Shapcote (Green Bay, WI; Steubenville, OH: Aquinas Institute; Emmaus Academic, 2018), III q.22 a.3 ad 1).
18. Saint Thomas Aquinas, Summa Theologiae, III q.26 a.1 resp. (emphasis added).
19. “…of the Man may be said what belongs to the Divine Nature, as of a hypostasis of the Divine Nature; and of God may be said what belongs to the human nature, as of a hypostasis of human nature,” yet, he adds the necessary caveat, “although we do not distinguish things predicated of Christ, yet we distinguish that by reason of which they are predicated” (Summa Theologiae, III q.26 a.1 resp.).
20. St. Irenaeus, Against Heresies, III.18.7, A. Roberts and W. Rambaut (trans), in A. Roberts, J. Donaldson, and A.C. Coxe (eds), Ante-Nicene Fathers, Vol. 1 (Buffalo, NY: CLPC, 1885).
21. Origene, Omelia 8 sulla Genesi, 6.8.9, PG 12, 206–209, UL martedì V settimana TO, LO III, 160‑162.
22. “O marvelous exchange! Man’s Creator has become man, born of the Virgin. We have been made sharers in the divinity of Christ who humbled himself to share our humanity,” Catechism of the Catholic Church 526 (The Liturgy of the Hours, Evening Prayer of 1 January, Antiphon I).
23. The Roman Missal: Renewed by Decree of the Most Holy Second Ecumenical Council of the Vatican, Promulgated by Authority of Pope Paul VI and Revised at the Direction of Pope John Paul II, Third Typical Edition. (Washington D.C.: United States Conference of Catholic Bishops, 2011), Preface III of the Nativity of the Lord. (cf. also Giovanni Zaccaria, “Exchange between the divine and the human. Christmas Preface III,” Omnesmag.com (https://www.omnesmag.com/en/resources-2/christmas-preface-iii/).