Seleucia Pieria was founded as a port city in the late 4th–early 3rd c. BCE, and several decades later became the chief port of Antioch. The city was an important node in eastern Mediterranean exchange, despite recurring problems with its harbor silting up, up until the early to mid 6th c. when multiple earthquakes ravaged the city to the point of abandonment in the late 6th c. (Erol and Pirazzoli 1992: 320–325)
Erol, O and Pirazzoli, P.A. "Seleucia Pieria: an ancient harbour submitted to two successive uplifts" The International Journal of Nautical Archaeology 21 317-327