John Raithuensis or RAITHENUS, i.e. of Raithus or Raitku (τοῦ ῾Ραϊθοῦ), begumendos or abbot of a monastery at Elim, or the Seventy Springs, on the western coast of the peninsula of Mount Sinai, flourished in the 6th century. He is celebrated on account of the friendly relations he sustained and the influence he exerted over John the Scholar, or John Climacus. It was at the desire of Raithuensis that Climacus wrote the work Κλίμαξ or Scala Paradisi, from which he derives his name, and to which Raithuensis wrote a Commendatio and Scholia. The Ε᾿πιστολὴ τοῦ ἁγίου Ι᾿ωάννου τοῦ ἠγουμένου τοῦ Ραίθοῦ Litteroe Joannis Raithuensis, addressed to Climacus, requesting him to undertake the work, and the answer of Climacus are given by Raderus in the original Greek, with a Latin version, in his edition of the works of Climacus (Paris, 1633, fol.). This version of the Litteroe of Raithuensis, and a Latin version of his Commendatio and Scholia, are given in various editions of the Bibliotheca Patrum: the Litteroe in vol. 3, edit. Paris, 1575; the Litteroe and Commendatio, vol. 5. edit. Paris, 1589 and 1654; the Litterce, Epistola, Commendatio, and Scholia, in vol. 6, pt. 2, ed. Cologne, 1618, and vol. 10, ed. Lyme, 1677. See Fabricius, Bibl. Gr. 9, 523-524; Ittigius, De Biblioth. Patrum. — Smith, Dict. Gr.s and Rom. Biog. 2, 601.