(Οὐαλεντῖνος), the celebrated Gnostic heresiarch of the second century, was a native of Egypt, whence he went to Rome, and there propagated his heresy, having seceded from the church, if we may believe Tertullian (c. Valent. 4) in consequence of being disappointed in the hope of obtaining a bishopric. The chronographers fix the time at which he flourished in the reign of Antoninus Pius, from A. D. 140, when they represent him as coming to Rome, and onwards. (Euseb. Chron. s. a. 2155; Hieron. s. a. 2156 ; Syncell. p. 351a.) Eusebius (Euseb. Hist. Eccl. 4.11) also tells us, on the authority of Irenaeus, that Valentinus came to Rome in the episcopate of Hyginus, flourished under Pius, and survived till the episcopate of Anicetus, about A. D. 140-155. (Comp. Euseb. Chron. and Hieron., s. a. 2159.) Some writers assign to him an earlier date, chiefly on the authority of the tradition, preserved by Clemens Alexandrinus (Strom. vii. p. 764), that he had heard Theodas, a disciple of St. Paul : hence Cave places him at the year A. D. 120. The two opinions may be reconciled by supposing, with Clinton, that Valentinus did not begin to propagate his heresy till late in life; and, supposing him to have been seventy years of age in A. D. 150, the first year of Anicetus, he would be twenty-five in A. D. 105, when it was quite possible that a disciple of St. Paul might be still alive. (Clinton, Fast. Rom. s. aa. 140, 144.)

Valentinus was one of the boldest and most influential heresiarchs of the Gnostic sect. A minute account of his doctrines, into which it is not consistent with the plan of this work to enter, will be found in the works quoted below : perhaps, for general readers, the brief but clear exposition of Valentinianism by Mosheim will be found the most useful.

There is also a good and brief account in Gieseler, which we extract, as the work is not so well known to the English reader, as that of Mosheim : -- From the great original (according to him, βυθός, προπάτωρ, προαρχή), with whom is the consciousness of himself (ἔννοια, σιγή), emanate in succession male and female aeons (Νοῦς or Μονογενής and ἀλήθεια, λόγος and ἀλήθεια, λόγος and ζωή ἄνθρωπος and ἐκκλησία, &c), so that 30 aeons together (distinguished into the ʼὈγδοάς, Δεκάς, and Δωδεκάς) form the πλήρωμα. From the passionate striving of the last aeon, the σοφία, to unite with Bythos itself, arises an untimely being (ἡ κάτω σοφία, ἐνθύημσις, Ἀχαμώθ, i. c. ), which, wandering about outside the pleroma, communicates the germ of life to matter, and forms the Δημιουργός of psychical material, who immediately creates the world. In this three kinds of material are mixed, τὸ πνευματικόν, τὸ ψυχικόν, τὸ ὑλικόν. The result of the course of the world is, that the two first should be separated from the last, and that τὸ πνευματικόν should return to the pleroma, τὸ ψυχικόν into the τόπος μεσότητος, where the Achamoth now dwells. In the mean time, two new aeons, Christ and the Holy Spirit, had arisen, in order to restore the disturbed harmony in the pleroma; then there emanated from all the aeons Jesus (σωτήρ), who, as future associate (σύζυγος) of the Achamoth, shall lead back into the pleroma this and the pneumatic natures. The σωτήρ united itself at the baptism with the psychical Messiah promised by the Demiurgus. Just so is the letter of the doctrines of Jesus for psychical men. On the other hand, the spirit introduced by the Soter or Saviour, is for the spiritual. These theosophic dreams were naturally capable of being moulded in many different ways; and, accordingly, among Valentine's disciples are found many departures from their teacher. The most important of his followers were Heracleon, Ptolemy, and Marcus.

It must, however, be remembered that our knowledge of his system is derived almost entirely from the works of the writers against the heresies, whose expositions of their opponents' views are often very unfair. Nothing is extant of his own works, except a few insignificant fragments, quoted by the writers referred to. (Irenaeus, ad v. Haeres. 1.1-7; Tertullian, c. Valentinianos ; Clem. Alex. passim ; Epiphanius, Haeres. 31; J. F. Buddeus, de Haeresi Valentin., appended to his Cave, Hist. Litt. s. a. 120, pp. 50, 51, ed. Basil.; Mosheim, de Reb. Christ. ante Const. pp. 371-389, Eccl. Hist. B. i. cent. ii. pt. 2.5. §§ 15-17, vol. i. pp. 191-193, ed. Murdock and Soames; Walch, Hist. d. Ketzereyen, vol. i. pp. 335-386; Schröckh, Christliche Kirchengeschichte, vol. ii. p. 359; Gieseler, Eccles. Hist. vol. i. pp. 140, 141, Davidson's transl., Neander, Kirchengeschichte, vol. i. pt. ii. pp. 704-731 )