The Hacı Bayram Mosque was built in the 15th century beside the ruins of the Temple of Augustus, incorporating the temple's remains into the complex. It is named for Hacı Bayram Veli, a Sufi mystic and scholar who founded the Bayrami order here in Ankara. His tomb within the mosque complex is one of the most visited pilgrimage sites in central Anatolia, particularly popular with Anatolian rural communities.
The mosque interior is decorated with tiles from Kütahya and has been restored several times over the centuries. The juxtaposition of the mosque's minaret and entrance porch against the Roman temple columns behind it is one of the more striking architectural moments in Ankara. The area in front of the mosque, where pilgrims gather and vendors sell religious goods, gives a vivid picture of popular Islam in modern Turkey.