Ashurbanipal was also known was Asenapper. Under his rulership, Assyria was said to have reached its greatest heights. Simultaneously, his brother ruled Babylon and they eventually warred against one another with Ashurbanipal coming off the victor. Ashurbanipal is best known for his literary interests compiled in a great library he formed at Nineveh excavated starting in 1845. Among the 22,000 clay tablets and texts were thousands of cuneiform writings including treatises on history, geography, astronomy, mathematical tables, medicine, grammar, as well as business documents. They are viewed as a valuable source of information about Assyria. He is mentioned in the Bible at Ezra 4:10, and his father is identified as Esar-haddon at Ezra 4:2.