The answer is: 31 years

2 Kings 22:1

Josiah's reign, lasting 31 years, is a remarkable period in the history of Jerusalem. He ascended to the throne at an early age—just eight years old! This might sound surprising today, as that’s more of an age to be in school than on a throne. Yet, he proved to be a beacon of hope amid a decline in moral priorities.

Josiah gets a prominent mention in 2 Kings, where readers discover how he uncovered the Book of the Law during temple renovations. Imagine that—cleaning up a building and finding a treasure that could change a nation! This wasn’t just a historical artifact; it brought the people back to the heart of their faith. They rediscovered the importance of covenant with God that many had long forgotten.

What’s interesting is that Josiah’s reforms were intensely localized. He re-instituted Passover celebrations in ways not seen since the days of the judges. Scholars debate the exact nature of those ancient traditions, but this wide-scale reinvigoration suggests that reviving memory can lead to significant change.

Furthermore, events during Josiah's reign echo wide themes in the Hebrew Scriptures—like reformation waves driven by genuine repentance—and the desire for knowledge and stability found in community. It’s meaningful to see how an individual act of faithfulness transformed an entire nation, highlighting the idea that every small choice we make can carry extraordinary breadth in the long narrative of human endeavor and faith.