Cornelius was a centurion of the Italian Cohort stationed at Caesarea Maritima, the Roman administrative capital of Judaea. 'A devout man, and one that feared God with all his house, giving much alms to the people, and always praying to God' (Acts 10:2). An angel appeared to him in a vision and bade him send to Joppa for Simon Peter.
Peter meanwhile was on the housetop of Simon the Tanner at Joppa, where he saw the great sheet let down from heaven with all manner of unclean animals and heard the voice: 'What God hath cleansed, do not thou call common.' At that moment Cornelius's messengers arrived. Peter went with them and preached Christ to the household at Caesarea. The Holy Spirit fell on the Gentiles as Peter spoke; they spoke with tongues and magnified God. Peter baptized them on the spot (Acts 10).
Cornelius and his household are the first Gentiles received into the Church by baptism — the turning point in the Acts of the Apostles, vindicated by the Council of Jerusalem (Acts 15). Tradition holds he was made bishop of Skepsis in Asia Minor by St. Peter and died there.