ARSIN'OE, the daughter of Ptolemy I., king of Egypt, and of Berenice, was b. about 316 B.C., and married in her 16th year to the aged Lysimachus, king of Thrace, whose eldest son, Agathocles, had already wedded Lysandra, the half-sister of A. Desirous of securing the throne to her own children, A. prevailed on her husband to put Agathocles to death; the consequences of which crime, however, were fatal to the Thracian mon arch; for Lysandra, having fled with her children to Seleucus in Asia, managed to induce him to declare war against her unnatural father-in-law. Lysimachus was slain, and Seleucus seized the kingdom. A. now sought refuge in Macedonia, which, however, was also taken possession of by Seleucus; but on the assassination of the latter, after a few months, by Ptolemy Ceraunus, the half-brother of A., she received a hypocritical offer of marriage from Ptolemy, who wanted to destroy her two sons, lest they should prove formidable rivals to his ambition. She consented to the union, and opened the gates of
the town in which she had taken refuge, but her children were butchered before her eves. She then tied to Egypt (279 p.c.), where she married her own brother, Ptolemy II. Philadelphus. These unnatural unions subsequently became common among the Greek kings of Egypt. It does not appear that A. had any children by her brother, though she was regarded by him with the deepest affection. He named several cities, and also au entire district, by her name. After her death, he ordered Dinochares, the architect, to build a temple to her memory, and roof the edifice with loadstones, so that her iron statue might seem to float in the air.