There is much to ponder in Dragoș Andrei Giulea’s provocative new book, which integrates and develops some of his previously published articles on the doctrinal debates of the fourth century. Giulea invites us to redefine the rival theological trajectories that generated and fuelled these tangled controversies.

Most significantly, this involves his identification of the ‘Antiochene trajectory’, a consistent set of metaphysical and doctrinal commitments most succinctly expressed in the response to Paul of Samosata (in the Letter of the six bishops, c. 268), and which represented the ‘forgotten orthodoxy of the third century’ (p. 68). This Antiochene grammar understood ousia and hypostasis as synonymous, and as referring to an individual divine substance. Since the Father alone was the ingenerate first principle, nothing – not even the Son – could be of the same ousia/hypostasis (for this would lead to rank Sabellianism). The Son was true and eternal God, but he was so as the Father’s Logos, Wisdom and Power; he was the only-begotten Son of the unbegotten Father. The Antiochene trajectory, then, secured the genuine personhood of the Son as both truly God and as distinct from the Father, but in order to avoid ditheism it had to subordinate the Son, and so acknowledge ontological degrees within the divine realm. For Giulea, these theological emphases characterised the mainstream of Trinitarian reflection in the East during the third century, and then subsequently enjoyed a fourth-century renaissance in the thought of Eusebius of Caesarea, and in many of the major councils of the 340s and 350s (especially the Council of Antioch in 341).

The main alternative theological vision was the ‘Nicene trajectory’. This cluster of doctrinal affirmations was shaped in response to the views of Arius, and underwent gradual refinement and development in the writings of Alexander of Alexandria, Athanasius, Eustathius, Marcellus and Apollinarius. Here, as in the Antiochene perspective, ousia and hypostasis were regarded as synonymous, but, unlike Antioch, they were understood as denoting a common substance that the Father shared with the Son. This principle, often expressed in ‘X from X’ language, allowed for true unity between the Father and the Son, cleansing the divine life of any ontological ‘degrees’ or hint of subordinationism. But the Nicene trajectory possessed an equal and opposite problem to that of Antioch: having guaranteed the unity of the Father and Son (and, later, the Spirit), it struggled to secure their distinct personal existence metaphysically. Step forward Basil of Caesarea, the hero of Giulea’s narrative, who, in a feat of Mendelian wizardry, synthesised the Nicene and Antiochene grammars by preserving their particular strengths and eliminating their besetting weaknesses. Basil snapped the synonymity of ousia and hypostasis, combining the Nicene use of ousia (that which is common or shared) with the Antiochene use of hypostasis (that which is individual or distinct). In this way, both the co-equal divinity and the individual subsistence of the Son were secured, and it was this doctrinal solution that triumphed at the Council of Constantinople in 381.

For readers somewhat wary of this undeniably clever (but perhaps a little too neat) overarching narrative, there are plenty of other intriguing claims to dig into. The consequence of Giulea’s remapping exercise is, inter alia, to shrink his third group – the ‘Arian trajectory’ – to include only Arius himself, Asterius, Eusebius of Nicomedia, Aetius and Eunomius. These men are distinguished by a strong insistence that the Son did not exist before his generation, and that he possessed any quasi-divine attributes only by grace, not by nature. Eusebius of Caesarea, by contrast, is not deemed to be part of this motley crew, but is instead included within the more mainstream Antiochene trajectory due to his higher estimation of the Son’s status (an argument which requires Giulea to dismiss Eusebius’ Letter to Alexander and Letter to Euphratius as inauthentic). The Homoian party, by contrast, does qualify as a distinct (albeit short-lived) fourth group. This was an imperially-influenced approach that vetoed the main terms of the controversy and commended only a vague relation of ‘likeness’ between Father and Son. In the second half of the book, Giulea also offers a subtle and detailed analysis of Basil of Caesarea’s gradual refinement of the meaning of ousia and hypostasis in his writings, with the Contra Eunomium marking the decisive crossing of the Rubicon.

There is much to commend in Giulea’s thesis, especially his careful tracing of the underlying metaphysical commitments of various writers during this period. His delineation of both the strengths and inconsistencies of particular ‘trajectories’, not to mention their protean complexity, is always thoughtful and clear-sighted. The further the lens begins to zoom out, however, the more the questions begin to emerge. Previous scholarly categories of the ‘Eusebian alliance’ or ‘moderate Origenism’ are dismissed for being unhelpfully diffuse, yet the author’s own ‘Antiochene trajectory’ arguably encompasses a comparable breadth of expression, and is permitted to evolve and develop flexibly over time. Indeed, Giulea further subdivides both the Antiochene and Nicene trajectories into a set of ‘metaphysical commitments’ and a set of ‘traditional tenets of faith’, each containing distinct emphases that sometimes jostle with (or even rub up against) one another. The taxonomic zeal on display here is again commendable, but the effect is to make each ‘trajectory’ even more conceptually capacious. Similarly, Giulea concedes that his foundational Antiochene document, the Letter of the six bishops, does overlap substantially with Origen’s thought, but rejects subsuming it within a greater ‘Origenist’ tradition on relatively slender grounds. The methodological problem of accurately disentangling genealogies of thought also rears its head in the analysis of the fourth century. Giulea is surely correct to note here the striking persistence of Paul of Samosata’s condemnation in 268 in the ecclesial memory of the councils of the 340s and 350s, but when (for instance) in the late 350s Basil of Ancyra self-consciously reuses terminology from Antioch 341, how can we be sure whether he is appealing to the authority of that tradition, or to the even older tradition of Antioch 268 that allegedly lies behind it?

There is, finally, the spectre of an alternative interpretation that looms over the whole work. It is possible that the Letter of the six bishops is inauthentic (as, for instance, Eduard Schwartz maintained), and that the document in fact dates from the second half of the fourth century. If this is the case, then Giulea’s painstaking work of tracing semantic and conceptual commonalties will have demonstrated not the profound influence of this text in a later controversy, but rather the projection of that later controversy’s characteristic terminology back into an imagined past. The ‘Antiochene trajectory’, such as it existed, would point backwards in time, not forwards. This remains, of course, just a possibility. What is clear is that Giulea has contributed a thought-provoking study, whose value lies less in its overarching thesis, and more in the consistent carefulness and insight of its analysis. For this reason, it will surely reward further study.