The prophet of the book — the FIRST voice of the second-temple age, prophesying in 520 BC alongside his younger contemporary Zechariah. His whole book is four oracles dated to the day across a single autumn (Elul to Kislev of Darius's second year), aimed at one goal: getting the stalled rebuilding of the temple restarted. The name means 'FESTIVE / my feast' (from chag, a pilgrim festival) — perhaps 'born on a feast day.' He is the only prophet in the Hebrew Bible given the title mal'ach YHVH, 'the messenger of Jehovah' (1:13). His hint that some in his audience 'saw this house in its former glory' (2:3) would make him an old man who remembered Solomon's temple before 587 — otherwise nothing personal is known. Ezra 5:1 and 6:14 name him and Zechariah from the outside as the prophets whose preaching got the work done. The Vulgate calls him Aggeus.