(Πτολεμαῖος), king of EGYPT, surnamed EPIPHANES, was the son and successor of Ptolemy IV.

He was a child of between four and five years old at the death of his father, B. C. 205; and the reins of government were immediately assumed in his name by the favourite and minister of the late monarch, Agathocles. The death of Philopator was even kept a secret for some time by the favourite, in order that he and his sister Agathocleamight possess themselves of the treasures in the palace, and concert measures for defending their power. Tlepolemus, their chief adversary, was absent from Alexandria, but notwithstanding this advantage, they were unable to face the indignation of the populace, and a violent sedition arose, in which Agathocles, his mother and sister, and all their chief supporters, were put to death [AGATHOCLEA]. After this Sosibius (son of the late minister of that name) obtained possession of the young king's person and the custody of his signet ring: but he was soon after compelled to yield them both to Tlepolemus, who assumed the chief administration of affairs. The new minister, however, though popular with the Alexandrians, and having the qualities of a brave soldier, was wholly incompetent for the position in which he was thus placed, and the affairs of the kingdom fell into the utmost disorder (Plb. 15.25_33, 16.21, 22; Just. 30.2). Mean-while the two monarchs, Philip king of Macedonia and Antiochus III. of Syria, had determined to take advantage of the minority of Ptolemy, and entered into a league to dispossess him of the crown, and divide his dominions between them. In pursuance of this arrangement Antiochus invaded Coele-Syria, while Philip reduced the Cyclades and the cities in Thrace which had still remained subject to Egypt. In this emergency the Egyptian ministers had recourse to the powerful intervention of Rome, and sent an embassy to place the young king and his dominions under the protection of the republic. The senate readily accepted the overture, and sent ambassadors to Egypt, one of whom, M. Lepidus, appears to have even assumed the title of guardian of Ptolemy [LEPIDUS, No. 7], while they commanded both Philip and Antiochus to desist from aggression, and restore the cities they had already conquered. The successes of the Syrian king had, in the meantime, been rapid and important. He defeated Scopas, the general of Ptolemy, in a decisive action at Panium, and shut him up within the walls of Sidon, where he was at length compelled by famine to surrender; and this advantage was followed up by the reduction of Jerusalem and the conquest of all Coele-Syria, Phoenicia, and Judea. While Antiochus himself was thus wresting from the crown of Egypt the possessions it had so long held in Syria, his generals reduced all the cities in Cilicia and Lycia which had hitherto been subject to the Egyptian monarchy. But his career of conquest was now checked by the Roman embassy, which commanded him to refrain from further hostilities, and restore all the conquered cities. In order to evade this demand without openly opposing the power of Rome, he concluded a treaty with Egypt, by which it was agreed that the young king should marrv Cleopatra. the daughter of Antiochus. and receive back the Syrian provinces as her dower. (Plb. 3.2, 15.20, 16.39, 18.33, 34, 28.17; Justin, 30.2. 3, 31.1; Liv. 31.2, 9 ; Appian, App. Syr. 1-3, Mac. 3; Hieronym. ad Daniel. 11.14-17; J. AJ 12.4.1.)

This treaty took place in B. C. 199, but the marriage was not actually solemnised until six years after. During this interval the peace between Egypt and Syria continued unbroken, while the administration of the former kingdom was placed in the hands of Aristomenes, a man who was every way worthy of the charge. We are told that, under his wise and vigorous government, the taxes were reduced, order restored, and the country recovered, in great measure, from the disorders of the reign of Philopator. Yet the period of his administration was not unmarked by civil troubles: a formidable revolt broke out in Lower Egypt, and it was not till after a long and arduous siege that Lycopolis, where the rebels had established their head-quarters, was taken, and the insurrection suppressed (Inscr. Rosett. pp. 3, 23, ed. Letronne Plb. 15.31; Diod. Exc. Vales. p. 574). At a subsequent period Scopas, the general who had opposed Antiochus, appears to have attempted to follow the example of Cleomenes, and excite a revolt in Alexandria itself, but his designs were discovered, and he was immediately put to death (Plb. 18.36, 37). It was in consequence of this last attempt that the guardians or ministers of the young king determined to declare him of full age, and the ceremony of his Anacleteria, or coronation, was solemnised with great magnificence, B. C. 196. It was on this occasion that the decree was issued which has been preserved to us in the celebrated inscription known as the Rosetta stone, a monument of great interest in regard to the internal history of Egypt under the Ptolemies, independent of its importance as having afforded the key to the discovery of hieroglyphics. (Plb. 18.38; Inscr. Rosett. ed. Letronne, Paris, 1841, published with the by Didot.)

Three years afterwards (in the winter of B. C. 193-192) the marriage of Ptolemy with the Syrian princess Cleopatra was solemnised at Raphia. (Hieronym. ad Daniel. 11.17; Liv. 35.13.) The war between Antiochus and the Romans was at this time on the eve of breaking out, and the former had doubtless hoped to attach the Egyptian king to his cause. But Cleopatra regarded the interests of her husband more than those of her father; and Ptolemy continued steadfast in his alliance with Rome. On the outbreak of the war he sent an embassy to the senate, with a large present of money and offers of assistance, both of which were, however, declined: and again in the following year (B. C. 190) we find him sending a fresh embassy to congratulate the Romans on their victory over Antiochus (Liv. 36.4, 37.3). But though the encroachments of the Syrian king upon his Egyptian neighbour had been one of the pretexts of the war, Ptolemy derived no advantage from the treaty which concluded it, and Antiochus, in defiance of his promise, still retained possession of Coele-Syria and Phoenicia.

We know very little of the reign of Ptolemy Epiphanes from the time that he himself assumed the government: but we are told that as long as he continued under the guidance and influence of Aristomenes, his administration was equitable and popular. Gradually, however, he became estranged from his able and virtuous minister, and threw himself more and more into the power of flatterers and vicious companions, until at length he was induced o rid himself of Aristomenes, who was compelled to take poison. Polycrates, who appears to have enjoyed great influence with the king after this period, shared in his vices and encouraged him in his effeminacy, studiously keeping him aloof from all part in military affairs. The only event which is recorded to us of this period is a second revolt ill Lower Egypt, which was successfully put down by Polycrates, and the leaders of the insurrection (who from their names must have been native Egyptians) were barbarously put to death by Ptolemy himself, n.100.185. (Diod. Exc. Vales. p. 574; Plb. 23.16; and see Letronne, ad Inscr. Rosett. p. 23.)

Towards the close of his reign Ptolemy appears to have conceived the project of recovering Coele-Syria from Seleucus, the successor of Antiochus, and had assembled a large mercenary force for that purpose: but having,byan unguarded expression excited the apprehensions of some of his friends, he was cut off by poison in the 24th year of his reign and the 29th of his age, B. C. 181. (Hieronym. ad Danicl. 11.20; Diod. Exc. Vat. p. 71; Porphyr. apud Euscb. Arm. p. 114; J. AJ 12.4.11.)

He left two sons, both named Ptolemy, who subsequently ascended the throne, under the names of Ptolemy Philometor and Euergetes II., and a daughter, who bore her mother's name of Cleopatra.