Until recently, little known, Lutitsa Fortress, today attracts more tourists, thanks to the excavations conducted by the team of Assoc. Prof. Dr. Boni Petrunova. The fortress is located in the Eastern Rhodopes, 6 km southwest of Ivaylovgrad. Near it is the abandoned village today Rogozovo. Buttercup is not just a fort. An area of ​​26 acres was enclosed within the fortress walls that housed an entire city which, if needed, could hide from the invaders the population of the surrounding settlements. The walls over 600 m in length are in very good condition and their height is kept up to 10 m in places. They outline an irregular ellipse in accordance with the terrain configuration. The entrance is just one, flanked by two rectangular towers. The fort has a total of 13 towers. The material of the fortress is marble, which explains why in the media space this magnificent monument became known as the "Marble City".

Historical evidence of the Ivaylovgrad area shows that this territory became part of the Bulgarian state as early as the beginning of the ninth century, when the border with Byzantium passed approximately in the same places. Buttercup reached its heyday in the thirteenth and fourteenth centuries. After the Ottoman invasion, the church continued to be used, and a small monastery was built at the foot of the hill.
       So far, two churches have been discovered by archaeologists. The earlier one, of which is the Episcopal Basilica, an extensive necropolis, the foundations of a dwelling tower, a water tank, at the bottom of which are discovered Thracian materials. The excavations revealed evidence that the site had been inhabited since the late Bronze Age until the seventeenth century. The fortress walls were erected in the IV century. In the 9th century Lutica became a bishop's center, mentioned repeatedly in the springs. The earlier church was three-nave, richly decorated with murals and plastic-shaped marble panels. The later one is small, with a double-sided roof covered with tiles. It was crowned with a cross that archaeologists found amidst the devastation.