Acts 18:8

And Crispus, the ruler of the synagogue, believed in the Lord with all his house; and many of the Corinthians hearing believed, and were baptized.

Crispus ... the ruler of the synagogue was one of the noble, or mighty, who accepted the Lord, of whom Paul said not many of them did so. This was one of those whom Paul baptized with his own hands (1 Corinthians 1:14); therefore, it is impossible to view the statements that "he believed" as excluding the baptism without which no New Testament conversion was ever completed.

Hearing believed, and were baptized ... There is only one plan of salvation for alien sinners; and here is a concise statement of it. The "plan" also included the repentance of those who accepted Christ.