A fragmentary Greek inscription on four stone fragments recovered from the Sanctuary of Apollo at Delphi between 1885 and 1910, first published by Émile Bourguet in 1905 and reconstructed by Adolf Deissmann in 1909. The fragments preserve a letter from the emperor Claudius to the city of Delphi, addressed to the Roman proconsul of Achaia, Lucius Iunius Gallio. The text refers to Gallio as "my friend and proconsul of Achaia" and dates Claudius's twelfth year of tribunician power, twenty-sixth acclamation as imperator — a regnal formula that fixes the letter to the first half of AD 52, with Gallio in office during AD 51 to 52. This is the single most important date-anchor in New Testament chronology. Acts 18 records that Paul came to Corinth, lived with Aquila and Priscilla, taught in the synagogue every Sabbath, and after eighteen months was hauled before the bema of the new proconsul: "But when Gallio was proconsul of Achaia, the Jews made a united attack on Paul and brought him before the tribunal." Gallio dismissed the case as an internal Jewish matter. The inscription proves Gallio was in office in exactly that window. Working backward from a known eighteen-month Corinthian residency, Paul's arrival in Corinth lands in late AD 49 or early 50 — and from that fixed point, the dating of Galatians, 1 and 2 Thessalonians, and the entire shape of the second missionary journey can be calibrated. The fragments are on display at the Archaeological Museum of Delphi. Sources: Émile Bourguet, De rebus Delphicis (1905); Adolf Deissmann, Paul: A Study in Social and Religious History (1912; English translation 1926); Joseph Fitzmyer, The Acts of the Apostles (Anchor Bible 31, Doubleday, 1998); Acts 18:12–17.
The Delphi inscription provides the single fixed calendrical point in New Testament chronology. By confirming Gallio's proconsulship in AD 51 to 52 and correlating it with Acts 18, scholars can anchor Paul's Corinthian ministry and calibrate the dating of multiple Pauline letters with unusual precision.