ARCHAEOLOGICAL EXPLORATIONS NEAR THE VILLAGE OF MIRKOVO (Boyan Dumanov – bdumanov@nbu.bg) The plateau of the hill covered an area of 0.95 ha, which is the approximate area of the fortress. The remains of the fortification were documented on the northern, western and southern edge of the plateau. The total length of the fortification wall was 212 m and it was 0.70 – 1.80 m wide, built of ashlars with an emplectum bonded with mortar. Buildings constructed of roughly-cut stones bonded with clay were documented in the fortress. A layer with traces from fire was documented in the building in Trench N–O8. A cistern with at least two construction periods was documented in Trench B´–C´16. The earliest structure was built of roughly-cut stones bonded with mortar. During the first construction period, the cistern measured 6.73 m by 5.07 m. During the second construction period, a new interior side of the cistern was built and its volume increased from 17 to 19 cbm. A pit of the 10th – 11th century was explored closed to the cistern. The cistern was built in the late 11th – 12th century and functioned until the middle of the 15th century.