Markeli

Markeli (; , Markellai; ) was a medieval Byzantine and Bulgarian frontier stronghold, the ruins of which are located in Karnobat Municipality, Burgas Province, southeastern Bulgaria. Dating to Late Antiquity, the castle lay some from the modern town of Karnobat. It was the site of two notable medieval battles between Byzantines and Bulgarians, the Battle of Marcellae of 756 and the Battle of Marcellae of 792.

==History== Markeli acquired its strategic importance in the late 7th century, when the establishment of the First Bulgarian Empire and its expansion turned it into a vital frontier stronghold just south of the Balkan Mountains. It would often change hands between Bulgarians and Byzantines, who would use it as a favourable starting point for military campaigns southwards and northwards respectively. Markeli first came under Bulgarian rule in 705, when it, together with the whole region of Zagore, was ceded to Bulgaria by Justinian II.