Arethas of Caesarea

Arethas was born at Patras, in the Peloponnese, about 860. He came to Constantinople, studied under Photios, and rose through the church until, around 902, he was made archbishop of Caesarea in Cappadocia, the senior metropolitan see of the Byzantine church after the patriarchate itself. He was still active in the 930s and is generally reckoned to have died about 939.

He was a difficult man, and the record shows it. He was drawn into the great scandal of his day, the fourth marriage of the Emperor Leo VI, and he changed sides in it more than once; his contemporaries did not let him forget it. He wrote sharp polemics, and he made enemies.

He also did something that scholarship has never stopped being grateful for. Arethas bought books, had them copied, and wrote in the margins.

In an age when ancient literature survived only as long as somebody was willing to pay a scribe, he paid. Manuscripts commissioned by him survive with the price he paid noted in them: a Euclid copied in 888, a Plato copied in 895 that is now in the Bodleian Library at Oxford and is one of the two oldest substantial manuscripts of Plato in existence, an Aristotle, a Lucian, and volumes of the Christian apologists, Justin Martyr, Athenagoras, Tatian, Clement of Alexandria. Several of those Christian works would be lost entirely without the copies he ordered. His own notes crowd the margins, arguing with the text.

That is the transmission of classical and Christian antiquity, done by one bishop with a budget and a habit.

His principal theological work is a commentary on Revelation. It is essentially a revision and expansion of the commentary written three centuries earlier by Andreas, his predecessor in the same see: Arethas kept Andreas's structure, added material from other fathers, and updated the whole. That version circulated widely in the Greek church and helped fix the Byzantine understanding of the last book of the Bible.

He also wrote scholia on other parts of Scripture, including fragments on Hebrews, homilies, letters, and a long series of occasional pieces on the disputes of his day.

He is on this wall for the ordinary reason that libraries matter. What we can read today of Plato, of Euclid, and of the second-century Christian apologists passed at one point through the hands of an argumentative Cappadocian archbishop who thought the copies were worth the money.

Sources: Arethas, Commentary on the Apocalypse (Migne, Patrologia Graeca, vol. 106); L. D. Reynolds and N. G. Wilson, Scribes and Scholars; N. G. Wilson, Scholars of Byzantium; The Catholic Encyclopedia (1913).