Sis Castle, locally known as Kozan Kalesi, lies in on a high rocky ridge next to the city of Kozan in the province of Adana in Turkey.
Sis Castle was built on a narrow and long spur of the Taurus mountains. The outline of the castle closely follows the rocks for almost 700 meters and spans two peaks of the spur. From this location the castle has clear intervisibility with the castles of Anavarza, Andil, Tumlu and Yilan.
Prior to the Byzantine period there is no record of a fortification at this site. Between September 704 and August 705 the small Greek settlement at Sis successfully repulsed an Arab attack with the help of the emperor's brother Heraclius. The settlement was situated at the foot of the mountain, which would have been topped with a fortified acropolis. In the early 800's Sis became part of the fortified frontier for the Abbasids, who planted a small colony on the site; the Caliph Al-Mutawakkil reconstructed its Byzantine defenses in the mid-9th century. Early in 962 Sis Castle was taken by the Byzantine army of Nikephoros II Phokas.
In 1113 the Rubenid Baron Thoros I captured the town and castle, which also experienced a devastating earthquake in the following year. The Byzantine Emperor John II Komnenos seized it in 1137. At some period before 1172 the Armenians reoccupied Sis and began construction at the site. The usurper Mleh is said to have been assassinated there in 1174. From 1177 on Sis Castle was the royal residence of Armenian Cilicia and seat of the Armenian patriarchs. Somewhere between 1180 and 1190 the town of Sis became the administrative capital of the kingdom, when this function was transferred from Anavarza.
During the reigns of King Leo I and his eventual successor, Hethum I, from 1187 until 1270, much ecclesiastical and military construction was undertaken at Sis Castle. The wife of Hethum I, Zapel, is credited with building a hospital there in 1241.
The history of Sis Castle becomes a repetitive account of Mamluk raids from 1266 to 1375. On ten separate occasions the Armenian capital or its immediate environs was successfully sacked by the Egyptians and their allies. In 1348 this misery was compounded by the arrival of the bubonic plague from Europe. The last Armenian king, Leo V, was betrayed and captured in the castle. Although Sis was the seat of the Armenian patriarchs from 1292 to 1873, the Katolikos resided there permanently only from the seventeenth century. A monastery for the patriarchs was not founded until 1734.
Sis Castle is freely accessible. The remnants of the castle itself may not be that spectacular but the view over the surrounding countryside certainly is.