The monumental Hadrian’s Gate was built to commemorate the visit of the Roman emperor Hadrian (AD 117-138) to Attaleia. The original structure stretched between two towers and has three equally spaced vaulted arches. The coffer blocks that form the vaults are elevated with pedestals; four thinner piers support the ones in the middle. The protruding architraves are supported by eight columns, four on each façade. These are aligned on the central axes of the transition segments, spaced 1.05 m from the bases of the pillars. The gate is 4.15 m wide and 6.18 m high. There is an architrave decorated with egg, bead, acanthus, and dentil reliefs between the arches and on the upper edge. The bronze inscription on the door that once bore the name of Hadrian and his titles is missing. Some of these bronze letters are on exhibition at the Ashmolean Museum in Oxford.

Although the arch dates to a later period stylistically, its construction probably started before the AD 120s to mark Hadrian’s first eastern campaign (AD 121-125). Its integration into the fortification wall and architectural characteristics add a monumental aspect to the arch. It is also an example of a main city gate.

There are two high quadrangular towers on either side of the gate. The bastion on the south side (Julia Sancta Tower) dates back to the Roman Imperial Period. The upper part was repaired with rubble stone and brick, and dentils were added. The inscription bearing the date of Hijri 617 (1220) on the bastion to the north of the gate indicates that it was rebuilt during the reign of Seljuk Sultan Alā ad-Dīn Kayqubād ibn Kaykhusraw.

The gate has been renovated and restored several times over the centuries, most recently in 1958.