Ptolemy (Gr. II ), the name of 13 Greek kings of Egypt, of whom the first three were the most important, and are treated in separate articles. Ptolemy IV., Philopator (222-205 B. C.), son of Ptolemy III., was mainly distinguished for cruelty and debauchery. The reign of Ptolemy V., Epiphanes, his son (205-181), was marked by the rapid decline of the Egyptian monarchy. His son Ptolemy VI., Philometor (181-146), by Cleopatra, daughter of Antiochus the Great of Syria, was aided in his wars with Syria, where he was some time a captive, by the Romans. Ptolemy VII., Physcon (the Fat, his usual cognomen, but called by himself Euergetes II., 146-117), brother of the last, with whom he reigned jointly for a time, and whose son he murdered, was driven to Cyprus by a rebellion of the Alexandrians on account of his cruelty, and afterward restored. He married his sister Cleopatra II., and afterward his niece Cleopatra III., and was a patron of letters and himself an author. Ptolemy VIII., Lathyrus, ruled in conjunction with his mother Cleopatra III. at intervals from 117 to 81, and married his sister Cleopatra IV. During his reign Thebes, having revolted, was destroyed.

Ptolemy IX. (Alexander I.), brother of the last, ruled for a while in conjunction with his mother. His wife was his sister Berenice III. Ptolemy X. (Alexander II.), step-son and husband of Berenice III., whom in 81 he put to death, was himself expelled and slain after a reign of 19 days. With him expired the legitimate line of the Ptolemies. Ptolemy XI., Nothus or the Bastard, also called Auletes or the Flute Player (80-51), an illegitimate son of Lathyrus, was one of the worst of the Ptolemies, and his reign was marked by complications with the Romans, whom he courted. He was expelled in 58, and restored in 55 by A. Gabinius, proconsul in Syria, for a bribe of 10,000 talents. Ptolemy XII. (51-48), his son, ruled in conjunction with his sister Cleopatra VI., whom he expelled in 49; for this the Romans made war, and he was lost in attempting to escape. Ptolemy XIII., Puer, younger brother of the last, married his sister, widow of Ptolemy XII., and was poisoned by her in 43. With him closes the line, although some reckon Caesarion, the son of Cleopatra by Caesar, as Ptolemy XIV. (See Cleopatra).