ARCHAEOLOGICAL EXPLORATIONS IN THE MARKELI FORTRESS (Dimcho Momchilov – karnobat.muzey@mail.bg, Rositsa Hristova) It was found that the fortification fosse is 18 m in width and 5.80 m in depth (the main part of which is an embankment). The main rampart is 5.50 m in height and 27 m in width, while the small southern front rampart is c. 1.20 m in height and 10 m in width. Excavations of the layers around the Late Antique and Mediaeval bridge were carried out. Several types of building technique were registered and building ceramics were found. The excavations on the western fortification wall were concentrated around the southwestern tower. Part of the fortification wall was discovered at 12 m in length. It is preserved up to six courses, 1.80 m in height. The wall was built in opus quadratum bonded with mortar, but there are some remains of opus mixtum. Remains of Proto-Bulgarian houses with pottery were discovered. The explorations on the eastern fortification wall were concentrated around tower No. 18 and to the north of it: alongside the wall up to tower No. 1 situated in the northeastern corner of the fortress. Remains of houses were discovered in front of tower No. 1: most likely dating after the 11th century in the upper layers and dated to the 9th – 10th centuries AD in the lower layers. The fortification wall between towers Nos. 18 and 1 is preserved up to 1.20 m in height. Several construction periods were registered. The exploration of an Early Mediaeval house of the First Bulgarian Kingdom dug into the inner southern rampart was accomplished.