Zephaniah's lineage given in the introduction of the book of Zephaniah traces him back to Hezekiah, presumably the king by that name. Zephaniah seems to have access to the court. He is also apparently at the time of Josiah, the right time to have had the aforesaid relationship to Hezekiah. We realize then that the prophet grew up during years of apostasy and Assyrian oppression.
Some of the references in Zephaniah to te apostasy may indicate that his ministry took place before Josiah's reforms of 621 B.C. However, it's also entirely possible that the reference to the "remnant of Baal" in 1.4 indicates the reforms are already under way. Another critical issue in the historical background is the identity of the invaders Zephaniah is concerned about. At this time they could be Assyrians, they could be Scythians, or, for that matter, they could be Babylonians. Again, we don't know with any clarity who the invaders are.
We do know that Zephaniah is discussing the kind of guilt that Judah bears for its unfaithfulness. He also attacks the surrounding nations for being no better than Judah, who stands condemned. As he wraps up his prophecies, Zephaniah proclaims salvation and restoration. The writing of Zephaniah divides clearly into themes of judgment and grace. God's fury will be poured out on those who do not trust him. Yet we see that his judgment is also used to gather people from all nations to worship the one true God. This is a strong message which causes us to look straight at the New Testament and Jesus as the divine warrior and soon coming king.