Antiochus VIII Epiphanes/Callinicus/Philometor, nicknamed Grypus (hook-nose) was son of Demetrius II Nicator and was crowned as a boy in 125 BC after his mother Cleopatra Thea had killed his elder brother Seleucus V Philometor, ruling jointly with her. After Antiochus defeated usurper Alexander II Zabinas in 123 BC his mother tried to poison him with wine, but the suspicious king forced her to drink the cup herself. He married the Egyptian princess Tryphaena, but in 116 BC his half-brother and cousin Antiochus IX Cyzicenus (see Antiochus VII Sidetes) returned from exile and a civil war began. Cyzicenus' wife, also named Cleopatra, was a half-sister of Tryphaena and was eventually killed in a dramatic fashion in the temple of Daphne outside Antioch, on the order of Tryphaena. Cyzicenus eventually killed Tryphaena as revenge. The two brothers then divided Syria between them until Grypus was killed by his minister Heracleon in 96 BC. Five of his sons succeeded him.

Despite political shortcomings, Grypus was a popular king. His ugly, lazy appearance on coins (common among the last Seleucids), together with stories of his lavish banquets, made posterity believe his dynasty was degenerated and decadent. This was however a conscious image, an invocation of the hellenistic idea Tryphe - meaning good life, which the last Seleucids strove to be associated with, as opposed to the exhausting civil wars and feuds which troubled their reigns in reality.