Behind the basilica is the Prytaneion, where religious ceremonies , official receptions and banquets were held. The sacred flame symbolizing the heart of Ephesus was kept constantly alight in the Prytaneion. The construction of the building dates to the 3rd century B.C, during the reign of Lysimachos, but the ruins of the complex dates to the Augustan age.
The four-cornered pit in which the sacred fire is burned is a relic from the reign of Lysimachos. The front of the building is four columns, beyond the columns is a courtyard surrounded by a portico, and on the north is the center of the building, the ceremonial hall, and its side rooms. The eternal flame was here in the center of the ceremonial hall, the red color on the floor determined the location of the flame. Towards the back, there was a large area with wooden roof, the base of an altar is still recognizable today.
The double columns on the corners of the hall held up the wooden roof. During excavations, archeologists found 2 artemis statues, which are now presented in Ephesus museum.