Collection of books used for reading or study, or the building or room in which such a collection is kept. The origin of libraries came in the 3rd millennium BC, when records on clay tablets were stored in a temple in the Babylonian town of Nippur. In the 7th century BC, the Assyrian king Ashurbanipal assembled and organized a collection of records, of which some 20,000 tablets and fragments have survived. The first libraries as repositories of books were those of the Greek temples and those established in conjunction with the Greek schools of philosophy in the 4th century BC. Important libraries of the ancient world were those of Aristotle, the great Library of Alexandria with its thousands of papyrus and vellum scrolls, its rival at Pergamum that included many works on parchment, the Bibliotheca Ulpia of Rome, and the Imperial Library at Byzantium set up by Constantine the Great in the 4th century AD. China also has a long tradition of record keeping and book collecting, in private libraries as well as in centralized government libraries. Extant Greek and Roman literary works were preserved alongside the early Christian literature in Constantine's library and, beginning in the 2nd century, in libraries of monasteries. The loss of the Great Library at Alexandria, which was burned to the ground in the late third century AD, was devastating. The Alexandria library had probably been established by Ptolemy I Soter (305-285 BC), who also founded the Museum ('shrine of the Muses'), initially creating both institutions as annexes to his palace. Later in the Ptolemaic period, another large library was created, probably within the Alexandria serapeum, but this too was destroyed in 391 AD.