EUTHALIUS, yu-thê'lî-us : The putative author of certain matter introductory to the Epistles of Paul, the Catholic Epistles, and the Acts, comparable to the Masorah of the Old Testament. As pointed out by Dean Robinson, the material has grown gradually. First a new system of writing the New Testament books was adopted from the schools of grammar and rhetoric; to facilitate the public reading in service, only so much was put in one line as could be pronounced in one breath, in place of the lines of equal length without punctuation or word division of the older manuscripts (א B, A, C). Jerome did the same for the Latin text and Hesychius of Jerusalem in the sixth century for the Greek prophets. The first "Euthalius" supplied about the middle of the fourth century tables of chapters and of the Old Testament quotations in the New Testament, with three prologues to the Epistles and Acts, including biographical and chronological researches. In 396 a short account of Paul's martyrdom was added and perhaps other parts of the work, as the Stichometry (q.v.) and the collation with the famous Codex Pamphili at Cæsarea, also the division of "the Apostle" into fifty-seven lections (Gk. anagnōseis). The so-called hypotheseis (argumenta), short introductions to each book, originally a part of the pseudo-Athanasian Synopsis scripturœ sacrœ, were afterward incorporated in the Euthalian apparatus in most Greek manuscripts and in the commentary of the so-called Oecumenius.

According to Zaccagni "Euthalius" was a deacon of Alexandria when he edited the Pauline epistles (458), and bishop of Sulke (an unknown Egyptian city, perhaps Pselche) in the time of Athanasius II. of Alexandria (489-496) when he published the Acts and Catholic Epistles. This theory was based upon a chronological datum found in only a few manuscripts of the Martyrium Pauli and now generally held to be a late addition. Ehrhard supposed "Euthalius" to be an intentional alteration of "Evagrius" (found in Codex H and a Naples MS.), made when Evagrius Ponticus (q.v.) came to be suspected of heresy. Von Soden proposed a new solution of the problem. There was a Bishop Euthalius of Sulci in Sardinia in the seventh century whose confession of faith, composed in the time of the Monothelite controversy, Wobbermin discovered in a manuscript of the Lawra, while von der Goltz found a quasidevotional monologue, Eis emauton, of the same in a manuscript of Chalcis, identical with the so-called "Prayer of Euthalius" contained in many Armenian Bibles. Von Soden accordingly conjectured that all the Euthalian apparatus originated in the seventh century. His theory has been severely criticized (cf. F. C. Conybeare in ZNTW, v., 1904, pp. 39-52; T. Zahn, NKZ, xv., 1904, pp. 305-330, 375-390; J. A. Robinson, in JTS, vi., 1905, pp. 87-90), and neglects late investigations, such as Robinson's convincing argument that the oldest materials must have existed before 396 and Von Dobschütz's induction from the Syriac versions that the work in its fuller form lay before Philoxenus of Mabug when he translated the New Testament into Syriac in 508. Either there must have been another Euthalius older than the bishop of Sulci (to whom perhaps the title "bishop of Sulci" was given by confusion with the latter), or the seventh century Euthalius used the work of an unknown earlier writer, adding perhaps some new matter of his own.

Only a full examination of all New Testament manuscripts and the versions can throw new light on the question. A new edition of the Euthalian apparatus is needed, as Zaccagni's first edition was based on only a few manuscripts. A greater difficulty is that of reconstructing the true text used and approved by Euthalius. What is called the Euthalius Codex in Tischendorf is but a single manuscript of comparatively recent date.