Magas was the first-born son of the Macedonian noblewoman Berenice and her first husband, Philip, who had served as a military officer in the campaigns of Alexander the Great.

[10] Berenice’s mother was the niece of the powerful regent Antipater[10] and was a distant collateral relative to the Argead dynasty.

[12] Magas was thus a stepson to Ptolemy I; he became an Egyptian prince living in his stepfather's court and was a member of the Ptolemaic dynasty.

[3] Magas then married Apama II, his third maternal cousin and one of the daughters of Seleucid King Antiochus I Soter and Stratonice of Syria.

[15] After the death of Magas, Apama II broke the marital alliance between her daughter Berenice II and Ptolemy III and proposed her daughter and the throne to Demetrius the Fair, son of the Antigonid king Demetrius I Poliorcetes, who became the new king of Cyrene.

[15][18] Ashoka also claims that he encouraged the development of herbalism, for men and animals, in the territories of the Hellenistic Kings.

Here in the king's domain among the Greeks, the Kambojas, the Nabhakas, the Nabhapamktis, the Bhojas, the Pitinikas, the Andhras and the Palidas, everywhere people are following Beloved-of-the-Gods' instructions in Dhamma.

Later, Magas, having been raised in part at the Ptolemaic court, must also have received first-hand accounts of India from his stepfather Ptolemy I, a former general in Alexander's campaigns.

The predecessor of Magas in Cyrene, the Ptolemaic governor named Ophellas, had also been one of the Alexander's officers in India, in charge of one of his triremes during the expedition down the Indus River.