Abstract: In the recent explosion of scholarship on the Arian controversy, the years immediately after Nicaea have been comparatively neglected. This is partly because the prevailing view in the English-speaking world is that either there was no real theological controversy at all during the years 325-345, merely a general distaste for the activities of Athanasius of Alexandria, or that there was a general fear throughout the East of the theology of Marcellus of Ancyra, uniting Eastern bishops against him. This book argues that neither of these positions can be sustained on the basis of the available evidence. It examines closely the evidence for episcopal attendance at the important councils of these years, and shows that all were demonstrably partial; that there was never a majority of politically active Eastern bishops against Marcellus, Athanasius, or their fellow supporter of Alexander, Eustathius of Antioch; and that Marcellus was deposed for theological opinions which he did not hold in the manner attributed to him. These years are best made sense of by returning to the idea of two theological and political alliances at war with one another before, during, and long after Nicaea, which only began to fragment in the early 340s after the death of Eusebius of Nicomedia and the falling-out of Marcellus and Athanasius over the so-called ‘Western Creed of Serdica’.

Keywords: Marcellus of Ancyra, Arian controversy, Nicaea, Serdica, Athanasius of Alexandria, Eustathius of Antioch, Eusebius of Nicomedia, council