The library of Celsus is an ancient Roman building in Ephesus, Anatolia, now part of Selçuk, Turkey. It was built in honor of the Roman Senator Tiberius Julius Celsus Polemaeanus (completed in 135 AD) by Celsus' son, Gaius Julius Aquila (consul, 110 AD). Celsus had been consul in 92 AD, governor of Asia in 115 AD, and a wealthy and popular local citizen. He was a native of nearby Sardis and amongst the earliest men of purely Greek origin to become a consul in the Roman Empire and is honored both as a Greek and a Roman on the library itself. Celsus paid for the construction of the library with his own personal wealth.
The library was built to store 12,000 scrolls and to serve as a monumental tomb for Celsus. Celsus is buried in a sarcophagus beneath the library, in the main entrance which is both a crypt containing his sarcophagus and a sepulchral monument to him. It was unusual to be buried within a library or even within city limits, so this was a special honor for Celsus.
Ephesus (//; Greek: Ἔφεσος Ephesos; Turkish: Efes; ultimately from Hittite Apasa) was an ancient Greek city on the coast of Ionia, three kilometers southwest of present-day Selçuk in İzmir Province, Turkey. It was built in the 10th century BC on the site of the former Arzawan capital by Attic and Ionian Greek colonists. During the Classical Greek era it was one of the twelve cities of the Ionian League. The city flourished after it came under the control of the Roman Republic in 129 BC. According to estimates Ephesus had a population of 33,600 to 56,000 people in the Roman period, making it the third largest city of Roman Asia Minor after Sardis and Alexandria Troas.