The earliest known inscription in Hebrew is the Khirbet Qeiyafa Inscription (11th — 10th century BCE), if it can indeed be considered Hebrew at that early a stage. By far the most varied, extensive and historically significant body of literature written in the old Classical Hebrew is the canon of the Hebrew Bible. The Bible is not a single, monolithic piece of literature because each of these three sections, in turn, contains books written at different times by different authors, written from the 8th to the 2nd century BCE. It is the primary source of ancient Israelite mythology, literature, philosophy and poetry. All books of the Bible are not strictly religious in nature; for example, "The Song of Songs" is a love poem and, along with "The Book of Esther", does not explicitly mention God.