The Roman theatre of Miletus was built under the Roman emperor Trajan (98 -117 AD) over a much older Hellenistic theatre. While the overbuilt theatre had 5,300 seats, the Roman building was designed for around 15,000 spectators. From the very beginning, the orchestra was also designed for gladiatorial and animal fights. The location of the theatre, which was unfavourable in many respects, was chosen for practical reasons in an existing hollow of the natural ground elevation. Only the third, upper tier was given a vaulted construction as a substructure. The axis of the theatre is thus diagonal to the axes of the Hippodamian city map, according to which most of the public buildings were oriented.
The columns in the middle of the lower tier carried a wooden imperial box covered with a canopy.

The city of Miletus shared the same fate as the cities of Herakleia on Latmos, Magnesia ad Maeandrum and Priene, they were founded in the wrong place. What nobody could know was that the river Mäander (Turkish: Büyük Menderes), due to the large quantities of sediments that it had always carried with it, slandered the entire Gulf, so that Herakleia became a place on an inland lake and Priene now lies far inland. Miletus itself lay on a promontory that protruded into the then existing Gulf. Milet gained its economic importance through its four ports, which were located in the usable bays around the headland.

According to tradition, Miletus was re-founded in 1053 BC by Ionic colonists. From the 8th century BC onwards, Miletus developed into an important transhipment point for trade with the Orient through the four ports. Purple fabrics from Miletus as well as other textiles, but also wool and olive oil were coveted trade goods. Miletus became one of the most important Greek cities and at times ruled the Aegean Sea. Miletus founded over 80 colonies. Miletus was called the Head of Ionia because of its extensive trade activities and the number of its colonies.

In the 7th century BC, the Greek cities on the west coast of Asia Minor came into conflict with the neighbouring empires of the Lydians and later the Persians. In the 6th century BC the city was first subdued by the Lydian king Kroisos, then by the Persians under Cyrus II. An uprising of the Ionian Greeks against the Persian Empire (Ionian uprising), starting from Miletus, failed. Miletus was conquered and destroyed by the Persians in 494 BC.

The reconstruction of Miletus was carried out according to the ideas of Hippodamos of Miletus. Until the Alexander campaign the city was under Persian supremacy in the 4th century BC. In Hellenistic times different powers ruled in Asia Minor, thus also over Miletus. 133 B.C. Miletus was bequeathed to Rome together with the kingdom Pergamon and became part of the Roman province Asia.

Miletus remained of secondary importance in the following period, as the Romans chose Ephesus as the capital of their province Asia. Nevertheless, numerous representative buildings were erected in Miletus during the imperial period. Like Ephesus, there was an early Christian community in Miletus. The New Testament reports in Acts that the Apostle Paul, on his last missionary journey before returning to Jerusalem, said goodbye to the leaders of the church in Ephesus.

In late antiquity, i.e. between 280 and 560 AD, there was a sharp decline in population. To protect it from enemy raids, the great theatre was fortified and provided with a fort at the highest place to protect it. Houses were built in the auditorium. During this time Miletus was of particular importance as a bishop's seat. In Ottoman times, the princes of Menetsche temporarily chose their seat in Miletus and left numerous representative buildings. An example of this is the excellently preserved Ilyas Bey Mosque near the Faustina Baths. In the following years it became quiet around Miletus. Until a severe earthquake in 1955 there was a village called Balat on the ruins. After the earthquake, the settlement was moved to the south, outside the city area.