As a state established by khan Asparoukh, Bulgaria has been existing for more than 13 centuries. Thracians were the first settlers in the Bulgarian lands and their civilisation is evidenced by the numerous archaeological finds, uncovered tombs, discovered gold and silver treasures. Testimonies for the presence of life in the pre-historic ages have been preserved in the best-preserved Neolithic housings discovered world-wide - namely those off the town of Stara Zagora, in the "Bacho Kiro" cave off the town of Dryanovo and in the Magurata cave - close to the town of Belogradchik.aroundbulgaria.com Under the rule of Khan Tervel (700-718 AD), Bulgaria expanded its territory and turned into a major political force. Under Khan Kroum (803-814 AD) Bulgaria bordered with the empire of Carl the Great to the west, and to the east the Bulgarian troops reached the walls of Constantinople, the capital of the Byzantine Empire. The reign of Tsar Simeon I (893-927 AD) marked the "Golden Age of Bulgarian Culture", and the territory of his state reached the Black Sea and the Aegean Sea. During the reign of Simeon's successors, Bulgaria was weakened by internal struggles, the heresy of the priest Bogomil spread and influenced the teachings of the Cathars and Albigenses in Western Europe.