Ayasuluk Fortress (also known as Selçuk Fortress) stands atop a high hill. It was built by the Byzantines in the 6th century and later fortified and rebuilt by the Turks after their conquest of the region in the 12th century. The need for such a powerful citadel arose due to the retreat of the Aegean Sea several kilometers eastward in this region.
In ancient times, the port city of Ephesus flourished. The retreat of the sea from ancient Ephesus was a gradual process, with key stages as follows:
1. Initial Problem (1st–2nd centuries AD): The sea began to silt up due to sediment from the Cayster River (modern Küçük Menderes) and deforestation upstream (which increased erosion). As early as Emperor Claudius` reign (41–54 AD), harbor dredging became necessary.
2. Critical Period (3rd–5th centuries): By 300 AD, the harbor had become so shallow that large ships had to dock 3 km from the city. The Byzantines in the 6th century (under Justinian) attempted to build canals but failed.
3. Point of No Return (7th century): By 610 AD, the harbor had completely silted up, and the resulting swamps caused malaria outbreaks. In the 7th century, the city was permanently relocated to Ayasuluk Hill (modern Selçuk). Today, the coastline lies 8 km from the ruins of the ancient port. Archaeologists have found 5th-century anchors in the fields near Pamucak village.
The hill of Ayasuluk was named after John the Theologian, who was buried nearby. In Greek, the hill was called Agios Theologos ("Holy Theologian"). Here, under Emperor Justinian I (527–565 AD), construction began on the fortress to protect the new city and the Basilica of St. John, built over the apostle’s tomb.
During the Byzantine period, the settlement was called Agios Theologos; later, the Seljuk Turks renamed it Ayasuluk, and the modern town of Selçuk inherited this name. The fortress controlled roads from Ephesus into the interior of Anatolia and toward the coast.
Architecture of Ayasuluk Fortress
Byzantine Period (6th–11th centuries): A 3 km-long stone wall with 15 towers (up to 20 m high), built using blocks taken from ancient Ephesus.
Internal structures of the Byzantine fortress:
• A citadel at the hill’s summit.
• Water reservoirs (remains still visible).
• Underground passages leading to the Basilica of St. John.
Seljuk Period (12th–14th centuries): After the Turkish conquest in 1090, the fortress was rebuilt:
• The İsa Bey Mosque (1375) was added at its base.
• New gates were constructed in the eastern wall.
• The citadel was reinforced with brick masonry.
Ottoman Era: By the 16th century, the fortress had lost its strategic importance and was used as a quarry.
What Remains of Ayasuluk Fortress today?
• Walls and towers: The western wall with two towers is the best-preserved section.
• Byzantine mason marks are still visible on the stones.
• Ruins of the command post and water reservoirs.
• The İsa Bey Mosque, a unique blend of Seljuk and Byzantine architecture.
From the fortress walls, visitors enjoy panoramic views of the ruins of Ephesus, the Basilica of St. John and the Küçük Menderes River valley. The fortress is a hybrid of Seljuk and Byzantine architecture, with Hellenistic blocks repurposed from ancient temples and 12th-century Seljuk bricks. Many tourists visit Ephesus without realizing that just a few kilometers away lies this equally fascinating historical site.
