Andromachus was the son of Achaeus who was a wealthy nobleman who owned estates in Anatolia.
Since Achaeus was anxious to secure his father's release,[4] Ptolemy IV of Egypt’s chief advisor, Sosibius, regarded the captive nobleman as a very valuable piece to play in the political game.
When Achaeus did revolt, pushed by other circumstances, and without having made any compact with Egypt, there was even less reason to let Andromachus go.
Sosibius was very unwilling to part with such a valuable individual; but around 220 BC the Rhodians intervened on behalf of Achaeus, changing the situation radically.
Byzantium hoped to gain Achaeus' support against Rhodes and its allies.