Athens retained its position as the most prestigious seat of higher education, especially in the domains of philosophy and rhetoric, with considerable libraries and philosophical schools. Alexandria had the monumental Museum (i.e. research center) and Library of Alexandria which was estimated to have had 700,000 volumes. The city of Pergamon also had a large library and became a major center of book production. The island of Rhodes had a library and also boasted a famous finishing school for politics and diplomacy. Libraries were also present in Antioch, Pella, and Kos. Cicero was educated in Athens and Mark Antony in Rhodes. Antioch was founded as a metropolis and center of Greek learning which retained its status into the era of Christianity. Seleucia replaced Babylon as the metropolis of the lower Tigris.