It is assumed that even in the late Old Stone Age 40,000 to 10,000 BC, here lived people. Remnants of the Neolithic-6000-4000 BC were found, among them stone hammers, flint blade, household utensils that talk about activities related to hunting, preparing food, etc.
The most plausible is the claim that in the VI - IV century BC, the area was inhabited by Thracians, one of the most numerous Indo-European people in ancient times, the creator of a unique culture. At that time, the village was inhabited by the tribe usdikenzi who engaged in farming, stockbreeding and ceramic production. To this period can be attributed skeletons of horse and other animals, household utensils and one copy found in 1903, in a hill seven miles northwest of Letnitsa. In 1908, a Thracian tomb in the area Serodyak was found (where the ancient village of Varbitsa was located), the findings of which are kept at the National History Museum in Sofia. In the same area in 1957, students come to the crock pot with dirt, burnt dust and many coins. Given the description of Herodotus about the Thracian burial rituals, it can be argued that the skeletons found in the mounds of the Thracian chieftain buried according to custom, with his wife, horse, weapons and household items. They erected a mound on his grave, and then held racing games. Clay utensils sealed with burnt earth and dust were funerary urns of ordinary soldiers, and above them the hills were rising.
It is very likely around the Maarata Cave in the village of Krushuna to have existed sanctuaries of Thracian gods because the places of springs of water were considered sacred by the ancient peoples.
It consists of 23 silver-gold items for horse-trappings, with rich stories inscribed. There are several different groups of applications made by different masters in different times – open-worked, of real and mythical animals with a frame and background. However, their presence in a finding suggests that they belonged to a man from the times of Odrin ruler Kotis I - IV century BC. The Letnitsa treasure is one of the most significant monuments of Thracian art and is important for the study of the history of ancient Thrace. The region has many Thracian mounds that have not yet been studied.
In 74-65 BC, for the first time the Roman army of Gaius Julius Caesar advanced to the north of the Balkan Mountains. The province of Moesia was formed. Defence facilities were built, as well as roads and fortresses. At about 500 m away from the village of Krushuna, the fortresses Kaleto and Daran-baran (from Turkish Dari-ambaria). They were a good defence against invading tribes from the north-Goths, Carpi, Sarmatians, Vandals and others. Both fortresses were part of one system. Dari-ambari was the front side of the fort which houses the guards. The western side is natural and the rest is surrounded by a wall, whose foundations have been preserved ever since. In the region, many Roman coins, fragments of pottery, bricks, Roman plaque: “Evteator posferum” were found. As a fundament of a column in the church St. Theodore the Tryon in Letnitsa, a Roman capital is located, turned upside down, with the inscription “Alexander ...” probably a Roman general, from the time of Trajan and many others.
In the VI-VII century, the lands were populated by Slavs and proto-Bulgarians.
At the end of XIII century and the beginning of the XIV century, hesychasm made its way to these places. Through obedience, abstinence, patience and contemplation of nature, hesychasts aspired to union with God. The first Bulgarian hesychast was Theodosius of Tarnovo. His followers sought solitude in inaccessible areas, away from mundane life. Perhaps this is why these philosophers hermits sought for a retreat in the area off the village of Krushuna, near the Maarata Cave.
The Krushuna temple shows that hesychasts have had certain, albeit empirical, knowledge of geology.
Several monastic cells carved into the almost inaccessible travertine cliffs around the waterfall, laid the foundations of the Krushuna Middle-Age Monastery. Next to the cells or inside them, niches for icons, books, candles were carved in. The central rock church was hewed with an entrance, which has a triangular shape symbolizing the Holy Trinity. The entrance opens up the route for the sacred area in a prayer cell, which shape is like a dome, resembling a church vault. The entrance to a dwelling unit is 243 cm wide and 260 cm deep. In front of the entrance, there is a place carved for an icon and the entrance has grooves where the door used to stand. Another cell has an almost square hole. The entrance next to the base is 110 cm and its height is about 100 cm.
The square is known as a flat model of the world, and the cube carved into the sphere is a model of the kingdom of heaven. The numerical ratio of these elements of symmetry corresponds to the golden proportion and harmony of the musical variety. In these cells lived Hesychasts who were actively performing and directly involved activities related to the traditions of the Tarnovo Literary School. The Krushuna Hesychasts healed sick people, helped the blind to start seeing again. They were participants in a very interesting social experiment aimed at the emancipation of humanity and man’s ills by even denying death. The Hesychast was deeply excited by the problem of death and immortality of a man. According to them, the great man is humble. They believed that humanity needs a revolution of values whose definitive principles would be love, wisdom and truth. They had their followers and fans among the local population. This is shown by numerous enriched niches and shelters carved into the rocks where one could even spend the night in the rain. It is, therefore, appropriate to speak of the Krushuna hesychastic and spiritual centre.