The library which stands in a restored state at the end of the Curetes Street is one of the well-known buildings of Ephesus. Between 105 and 107 Tiberius Julius Celsus Polemaeanus was for one year the governor of the province of Asia in Ephesus. After his death his son Tiberius Julius Aquila built the library as a monumental tomb for his father. Celsus' tomb which is extremely beautiful lies in the narrow tomb chamber below the west wall. The construction was thought to be completed towards the 120s.
The Library of Celsus was destroyed in an earthquake in the 10th century; it was revealed by the excavations of the Austrian Institute of Archaeology in 1904 and was restored between 1970 and 1978.
As the library was built later than the Gate of Mazeus and Mithradates on the left and the structure believed to be an altar on the right, an architecture to cause visual aberration was applied to avoid the library's looking squeezed in between the already existing two buildings. For example, the podium which is reached by a number of steps is arched like a bow with a difference of 15 centimetres between the middle point and the edge. In the same way, the columns in the middle were built higher than the ones at the sides, thus trying to make the building look larger than it was.
The statues in the niches of the facade wall were found in the excavations of 1904 and were taken to Vienna; copies of these were put in their original places during restoration. According to the inscriptions on their bases, the statues represent the wisdom (sophia), knowledge (epis-teme), destiny (ennoia) and virtue (arete) of Celsus.
The columns of the upper storeys are smaller than those of the floor below. They carry triangular and semicircular pediments by turn. The interior of the library is plainer compared to the facade. In the west wall there is a big niche in the form of an apse. In this niche which lies on top of the tomb chamber there was a statue of Celsus. This statue was taken to the Museum of Archaeology of Istanbul. The two rows of niches in the side walls were for bookrolls. In front of the second row there was a wooden balcony. The back of the side walls was kept empty to prevent the books from dampness. Entering by the door on the right one can reach the tomb chamber of Celsus.
A candelabrum with seven branches standing on one of the stairs of the library was probably made by someone from the Jewish community living in Ephesus. To the right, on the base with inscriptions are listed the regions of the province of Asia of which Celsus was the governor, emphasizing that Celsus was an important personality. In the excavations of 1904 a fountain niche was found adjacent to the podium of the library. Furthermore, the frieze relating to the famous Parthian wars, in the present day on display in Vienna, was discovered arranged on either side of the fountain niche. This frieze is believed to belong to an altar which stood where the ruins are on the left.
The sarcophagus directly facing the library was discovered in an excavation carried out here by the museum. According to the inscription on it the sarcophagus belonged to a person called Dionysios.
The front of the library was designed as an auditorium. Thus, on the left were the stairs of the altar, on the west those of the library and on the right those of the stoa of Nero. In the 5th century in which Ephesus had lost its power the city walls were reconstructed and narrowed, and a gate was built in the middle of this auditorium. This gate can be distinguished easily by the difference of construction materials.
The sewers coming from the Curetés Street went on, running before the library, to the Agora whence it probably reached the sea. The round base in the auditorium on the side bordering the Marble Street was, according to one thesis, the base of a water clock.The other pieces of the water clock are on the east portico of the Mercantile Agora. How the watch worked is not known.