The Book of Enoch, or 1 Enoch, is an ancient religious work that was once a part of the Jewish and Christian canons. Enoch was the great-grandfather of Noah. The current known Book of Enoch contains a number of unique ideas on nephilim, angels falling from heaven, and an explanation on the need for the Great Flood. It also predicts the thousand-year reign of the Messiah. Scholars place different parts of the text as being written as early as 300 BC and the oldest parts around the first century AD. Thus, they claim this is a book that was added to over the years, just as many scholars state on the dates of much of the canonized Bible.