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.