Guide
Harmantepe Castle is a Byzantine fortress near the village of Harmantepe in the Söğütlü district of Sakarya, built in the twelfth or thirteenth century to defend the eastern frontier of the Byzantine empire. It stands on a small hill beside the stream running out of Lake Taşkısığı.
The walls are ten metres high and two metres thick, with six towers of five by five metres along them. Stone from the surrounding area was used; there is no brick, only rubble stone and lime mortar. The castle has five gates, the main one on the south side. Long unrepaired, its walls, gates and towers have been badly damaged, and years of neglect have left it covered in vegetation.
Standing in the broad Adapazarı plain, the castle is exposed, and the traces of a ditch thought to have been dug around it to strengthen its defence are unclear. Its construction matches that of Seyifler castle. Its date has been disputed: some researchers connected it to the ancient canal project of the sixth century that also gave rise to the Bridge of Justinian, but the finds from the castle have established that it belongs instead to the line of fortresses built west of the Sakarya river against the intensifying Turkish raids.
It is the soundest Byzantine castle in the province of Sakarya, and a decision has been taken to restore it and open it to visitors.
Getting there
The castle is reached from the centre of Söğütlü by 2.5 kilometres of asphalt road followed by 2.5 kilometres of unmade road.
