The Royal Library of Alexandria, or Ancient Library of Alexandria, in Alexandria, Egypt, was the largest and most significant great library of the ancient world. It flourished under the patronage of the Ptolemaic dynasty and functioned as a major center of scholarship from its construction in the third century B.C.E. until the Roman conquest of Egypt in 48 B.C.E. In Roman times, scholars used a related library called the Serapeum, located in another part of the city. This library was described as the "daughter library" and was also a temple to the god Serapis.