Another important issue concerning the writing of the Book of Genesis concerns when it was written. If Moses was the author or compiler of the events in Genesis then the book was written during his lifetime. Moses lived during a period of time that is known as the Late Bronze Age (about 1550 to 1200 B.C).
Area Of Dispute
The exact dates when Moses lived are still a matter of controversy. The reason is that the precise date of the Exodus of the children of Israel from Egypt is still debated. Two different dates, 1445 B.C. or 1290 B.C., are put forward to be the date of the Exodus.
1445 B.C.
Those that advocate a 1445 B.C. date do it on the basis of internal evidence from Scripture.
1 Kings 6:1 tells us that Solomon built the Temple in the fourth year of his reign over Israel.
And it came to pass in the four hundred and eightieth year after the children of Israel had come out of the land of Egypt, in the fourth year of Solomon's reign over Israel, in the month of Ziv, which is the second month, that he began to build the house of the Lord (1 Kings 6:1).
The fourth year of Solomon's reign was about 966 B.C. and 480 years before that would give us the date of approximately 1445 B.C. The wandering in the desert would have taken place during the 40 years after 1445 B.C. The first five books of the Old Testament would have been composed at that time.
Jepthath's Testimony
We also have the testimony of the Judge Jepthah.
While Israel dwelt in Heshbon and its villages, in Aroer and its villages, and in all the cities along the banks of Arnon, for three hundred years, why did you not recover them within that time? (Judges 11:26).
The statement that the people had been in the land for three hundred years fits with the date of the Exodus at 1445 B.C. The chronology will not fit with the 1290 date.
1290 B.C.
Those who hold the 1290 B.C. date do so without any internal biblical evidence to support their claim. They come up with this date from archaeological evidence that is much in dispute.
Summary
We conclude, therefore that Moses wrote the Book of Genesis since Scripture attributes the writing to him. But we cannot be certain as to the exact time he wrote. The Bible seems to argue for a 1445 B.C. date for the Exodus but there is no way we can be sure on this question.