Misionis Fortress (or Krumovo Kale) near Targovishte dates back to the period of the early Byzantine and medieval Bulgarian history, 4th-6th, 9th-10th, 12th-14th centuries. Misionis lasted for ten centuries, during which time it played a central role in the trade of the then Byzantine and Bulgarian medieval empire. The fortress has a strategic significance for the defence of the old capitols Veliki Preslav and Veliko Tarnovo. The town was wiped out in the 14th century by the Ottoman conquerors, who pillaged and burned it down.