[4] His father Achaeus was the second son of King Seleucus I Nicator and his first wife Apama I.
[5][6] According to surviving inscriptions, Alexander was already active and held high positions under his paternal uncle Antiochus I Soter.
[1] During the reign of his paternal cousin and brother-in-law Antiochus II Theos, Alexander was a very powerful figure in Anatolia.
[1] Between 261–244 BC in Magnesia ad Sipylum, he is noted in writing a letter about land allotments granted to soldiers and he was honored at Tralles.
[1] In the year 240 BC Alexander was still loyal to his nephew Seleucus II Callinicus, as he was the governor of Lydia, based at Sardis.