The Old Testament was written over a long period, with the earliest parts composed around 1500-1400 BC and the latest parts completed by about 400 BC. The Pentateuch (the first five books: Genesis, Exodus, Leviticus, Numbers, Deuteronomy) was likely written between 1446-1406 BC, possibly preserving much oral tradition before that. Historical books were written from roughly 1400 BC to 400 BC, often incorporating earlier oral traditions. Wisdom literature and prophetic books were written between the 10th century BC and the 5th century BC. Most of the prophetic books were finalized between the 5th and 2nd centuries BC. In summary, the Old Testament's composition spans roughly from the 15th century BC through to around the 4th century BC, with some parts possibly redacted or finalized later during the post-exilic period (after 538 BC) up to the 3rd century BC for some sections.
This long time frame reflects the diverse authorship and compilation of texts that form the Hebrew Bible or Old Testament.
