Acts 10 is one of the most important gospel texts in the New Testament. That text is followed by Acts 11:20 where, after rehearing the Acts 10 episode with Cornelius, Peter says:

Acts 11:19 Now those who were scattered because of the persecution that took place over Stephen traveled as far as Phoenicia, Cyprus, and Antioch, and they spoke the word to no one except Jews. 20 But among them were some men of Cyprus and Cyrene who, on coming to Antioch, spoke to the Hellenists also, proclaiming the Lord Jesus. 21 The hand of the Lord was with them, and a great number became believers and turned to the Lord. 22 News of this came to the ears of the church in Jerusalem, and they sent Barnabas to Antioch.

Persecution pushed the earliest Jewish Christians out of Jerusalem and it led to some spilling over with the gospel to “Hellenists.” Problem: “Hellenist” might more naturally mean “Greek-speaking Jews” (6:1; 9:29) but that would not form a decent contrast with v. 19 so most interpret this to mean “Greeks” or “Gentiles.” The non-Jewish Greek-speaking inhabitants of Antioch.
Their message? They “gospeled” the Lord Jesus. That is, their message was that Jesus was the Lord. This is short hand at a major level for what we read in Acts 11: the narrative arc from Israel to Jesus.