School of Tyrannus (lecture hall or school in Ephesus) may have been located near the Library of Celsus. Paul had been teaching in the Jewish synagogue in Ephesus for about "three month, arguing persuasively about the kingdom of God. But some of them became obstinate; they refused to believe and publicly maligned the Way. So Paul left them. He took the disciples with him and had discussions daily in the lecture hall of Tyrannus. This went on for two years, so that all the Jews and Greeks who lived in the province of Asia heard the word of the Lord."
Sources:
- Acts 19:1, 8-10
- Wood, John T., Discoveries at Ephesus: including the site and remains of the Great Temple of Diana London, 1877, https://archive.org/details/discoveriesateph00wood_0