First Roman military governor of Judea & Samaria, sent by Augustus [in 6 CE] to replace Archelaus who had been unable to end a decade of civil unrest that followed Herod's death. As a cavalry officer subordinate to Quirinius, imperial legate to Syria, who was instructed to confiscate Archelaus' estates & assess the wealth of the emperor's new provinces, Coponius conducted a census of Judeans & Samaritans to establish a basis for direct Roman taxation. This precipitated a tax-revolt led by radical Pharisees (Judah of Gamala & Zaddok), which Josephus identified as the root of a Jewish independence party that fomented the war with Rome 60 years later. Josephus himself did not report the fate of the tax revolt, but introduced it by noting that Coponius had imperial authority to perform executions. Luke (writing about the same time) claims that Judah "perished and all who followed him were scattered" (Acts 5:37), presumably by Roman troops commanded by Coponius. Luke does not mention Coponius but situates Jesus' birth during the census conducted "while Quirinius was governor of Syria" (Luke 2:2). 

References: Antiquities 18.2, 29-31.
                  _____, War 2.117.

Other resources on line:

• Coponius - article by R. Gottheil & S. Krauss in the Jewish Encyclopedia.

Bronze prutah minted in Jerusalem by Coponius. While the the coin bears traditional images acceptable to Jews [wheat on the face, a palm on the reverse], the inscription clearly proclaims occupation by imperial Rome. The letters [Greek, rather than Hebrew]  surrounding the wheat read: [K]aisa-ros ["of Caesar"] & the date [again in Greek letters] under the palm indicates the thirty-sixth year of Augustus' principate [= 6 CE], the year of Quirinius' census.