Titus is first mentioned in 2 Corinthians 2:13, where Paul refers to him as his brother. Titus accompanied Paul during his third missionary journey. He was a “Gentile guinea pig” so to speak, as a Christian not following Jewish traditions (i.e. circumcision). Titus helped Paul make his case that Gentiles did not need to obey Jewish laws.
During this journey, Paul sent Titus to Corinth to organize the collection of funds for the relief of the poverty-stricken Christians in Jerusalem. They met up again in Macedonia in ad 55, at which point Titus gave Paul a report on the church in Corinth (2 Corinthians 7). Titus returned to Corinth, accompanied by two others (possibly Luke and/or Barnabas), delivering Paul’s second letter to the church in Corinth (2 Corinthians 8).
After his first imprisonment in Rome, during his fourth missionary journey, Paul visited the island of Crete and left Titus to serve as pastor there. Later during this same journey, Paul wrote his letter to Titus, probably around ad 65. Zenas and Apollos (Titus 3:13) delivered it to Crete.
Paul planned to send Artemas or Tychicus (Titus 3:12) to replace Titus before winter and requested that Titus meet him in Nicopolis. According to the Roman historian Eusebius, however, Titus remained in Crete as the island’s first bishop.