Original: Antioch became the capital and court-city of the western Seleucid empire under Antiochus I , its counterpart in the east being Seleucia on the Tigris ; but its paramount importance dates from the battle of Ancyra ( 240 BC ) , which shifted the Seleucid center of gravity from Asia Minor , and led indirectly to the rise of Pergamum .
Simplified: Antioch became the capital and court-city of the western Seleucid empire under Antiochus I , its counterpart in the east being Seleucia on the Tigris .