(Πτολεμαῖος), king of EGYPT, was the youngest son of Ptolemy Auletes. He was declared king by Caesar in conjunction with Cleopatra, after the death of his elder brother Ptolemy XII., B. C. 47: and although he was a mere boy, it was decreed that he should marry his sister, with whom he was thus to share the power. Both his marriage and regal title were, of course, purely nominal: in B. C. 45, Cleopatra took him with her to Rome, but shortly after the death of Caesar she put the poor boy to death, after he had enjoyed his titular sovereignty a little more than three years, B. C. 43. (Porphyr. apud Euseb. Arm. p. 118; Hirt. B. Alex. 33; D. C. 42.44, 43.27; Strab. xvii. p.797; Suet. Jul. 35.)

Concerning the history of the Ptolemies in general, see Vaillant, Historia Plolemaeorum Regum Aegypti, fol. Amstel. 1701; Champollion-Figene, Annales des Lagides, 2 vols. 8vo. Paris, 1815; Letronne, Recherches pour servir à i'histoire d'Egypte, 8vo. Paris, 1823, and Recueil des Inscriptions Grecques en Egypte, 4to. Paris, 1842 ; Clinton, F. H. vol. iii. Appendix, ch. 5. Much light has been thrown upon the history of the earlier Ptolemies by Niebuhr, Kleine Schriften, pp. 179-305, and by Droysen, Hellenismus, vol. ii., but a good history of this dynasty is still a desideratum.

Of the coins of the Ptolemies it may be observed, that most of them can only be assigned to the several monarchs of the name by conjecture ; very few of them bearing any title but those of ΠΤΟΛΕΜΑΙΟΥ ΒΑΣΙΛΕΩΣ. Hence they are of little or no historical value. (See on this subject Eckhel, vol. iv. pp. 4-25; Visconti, Iconographie Grecque, vol. iii. chap. 18.)