The Basilica, which starts from the Gymnasium before the Odeion and extends to the foundation chambers on the west was originally devoted to commerce, having been constructed as an exchange. The Basilica was constructed in three sections during the reign of Augustus over a gallery with a single hall, which was located during the Hellenistic period. This is a typical Roman basilica, one unusual feature of which is columns, most of which were restored and installed here.
Its location next to the State Agora permitted commercial transactions to be carried out more rapidly. It has been established that to the east of the Basilica there was a stoa, which underwent major alterations. From here, there were three entrances to the Basilica of which the largest was in the middle. It was here that the statues of Augustus and his wife Livia, on display in the Ephesus Museum, were found. The Basilica is 165 metres long and contains columns with typical 1st century A.D. bulls' heads and Ionian capitals.
The Fountain of Laecainus Bassus
On the southwest corner of the State Agora we find the remains of a fountain. According to an inscription which was turned up during the course of excavation, construction of this fountain was ordered by Gaius Laecanius Bassus in 80 AD. The facade of this fountain constructed by Bassus, one of the wealthy man of Ephesus, was richly decorated,and consisted of two storeys which faced the street. The statues of Tritons and Muses, which were found at the fountain, are now on display at the Ephesus Museum. Because of the enormous size of the fountain it has been referred to as the "Water Palace". This fountain is connected to another fountain which is located just opposite it to the west of the State Agora, and also at the same time to a storage cistern. The main section consists of a body in the form of a semicirle and was built in the 2nd century AD.
The fountain underwent repairs in the reign of Constans and Constantius II (337-350) when the present wings were added. In inscriptions, this structure is referred to as the Nymphaion. It is the terminal point of the Aqueduct of Sextilius Pollio, which was built during the reign of Augustus between 7 -15 AD. The aqueduct was 3.5 kilometers long, and its remains may still be seen along the Selcuk-Aydin highway. There was a cistern in the upper part of the fountain, and the surroundings of the structure were decorated with statues of the Emperor.