Rhesaina (Rhesaena, Resaena - numerous variations of the name appear in ancient authors) was an important town at the northern extremity of Mesopotamia, near the sources of the Chaboras (now the Khabur River. It was on the way from Carrhae to Nicephorium, about eighty miles from Nisibis and forty from Dara. Nearby, Gordian III fought the Persians in 243, at the battle of Resaena. It is now Ra's al-'Ayn, Syria.
Its coins show that it was a Roman colony from the time of Septimius Severus. The Notitia dignitatum (ed. Boecking, I, 400) represents it as under the jurisdiction of the governor or Dux of Osrhoene. Hierocles (Synecdemus, 714, 3) also locates it in this province but under the name of Theodosiopolis; it had in fact obtained the favour of Theodosius the Great and taken his name. It was fortified by Justinian. In 1393 it was nearly destroyed by Tamerlane's troops.
Le Quien (Oriens christianus, II, 979) mentions nine bishops of Rhesaena:
- Antiochus, present at the First Council of Nicaea (325);
- Eunomius, who (about 420) forced the Persians to raise the siege of the town;
- John, at the Council of Antioch (444);
- Olympius, at the Council of Chalcedon (451);
- Andrew (about 490);
- Peter, exiled with Sevenian (518);
- Ascholius, his successor, a Monophysite;
- Daniel (550);
- Sebastianus (about 600), a correspondent of Gregory the Great.
The see is again mentioned in the 10th century in a Greek Notitia episcopatuum of the Patriarchate of Antioch (Vailhé, in "Echos d'Orient", X, 94). Le Quien (ibid., 1329 and 1513) mentions two Jacobite bishops: Scalita, author of a hymn and of homilies, and Theodosius (1035). About a dozen others are known.
- Annuario Pontificio 2013 (Libreria Editrice Vaticana, 2013, ISBN 978-88-209-9070-1), p. 958]
- This article incorporates text from a publication now in the public domain: Herbermann, Charles, ed. (1913). "Rhesæna". Catholic Encyclopedia. Robert Appleton Company. The entry cites:
- Revue de l'Orient chrét. VI (1901), 203;
- D'Herbelot, Bibl. orientale, I, 140; III, 112;
- Carl Ritter, Erdkunde, XI, 375;
- William Smith, Dictionary of Greek and Roman Geography, s. v., with bibliography of ancient authors;
- Müller, notes on Ptolemy, ed. Didot, I, 1008;
- Chapot, La frontière de l'Euphrate de Pompée à la conquête arabe (Paris, 1907). 302.