The Apostle Paul taught the presbyters of Asia for 3 years:
“Therefore watch, and remember that for three years I did not cease to warn everyone night and day with tears” (Act. 20:31)
The Apostle Paul taught the Christians in Ephesus for 2 years and 3 months:
“And he went into the synagogue and spoke boldly for three months, reasoning and persuading concerning the things of the kingdom of God. But when some were hardened and did not believe, but spoke evil of the Way before the multitude, he departed from them and withdrew the disciples, reasoning daily in the school of Tyrannus. And this continued for two years, so that all who dwelt in Asia heard the word of the Lord Jesus, both Jews and Greeks” (Act. 19:8-10)