What does Acts 7:1 mean?

Stephen is a Hellenist Jew: he is not from Judea and probably speaks more Greek than Aramaic. He is also a strong Jesus-follower and one of the first deacons of the early church (Acts 6:1–7). He has been arguing with other Hellenist Jews. We don't know what, exactly, the argument is about, but his opponents cannot overcome his logic or the power of the Holy Spirit in him, so they falsely accuse him of disrespecting the Mosaic law and the temple (Acts 6:8–15).

The Hellenist Jews bring Stephen to the Sanhedrin where the high priest asks him to make his defense. In Acts 4:6, when Peter and John were arrested, Annas is named as the high priest. It's unclear how much later this event in Acts 7 takes place. According to Jewish records, Caiaphas was the high priest until AD 36, Jonathan until AD 37, and Theophilus until AD 41. Important to understand is that Caiaphas was Annas' son-in-law, and Jonathan and Theophilus were Annas' sons. So it seems Annas held significant control over the priesthood from his own period, starting in AD 6, until AD 44, Jonathan's second term.

The last recorded time the Sanhedrin tried Jesus-followers, they told the apostles to stop preaching about Jesus and then beat them (Acts 5:40). This didn't deter the apostles. Not only did they continue preaching in the temple (Acts 5:42), several priests came to faith in Christ (Acts 6:7). But even though more and more Jews were following Jesus, the Jesus-followers were losing favor with the people.