Was Lepenski Vir an ancient Sun or Pleiades observatory?

In this work we consider some old hypotheses according to which remarkable mesolithic village Lepenski Vir (9500 – 5500 BC) at the right (nearly west) Danube riverside in the Iron gate in Serbia was an ancient (one of the oldest) Sun observatory. We use method recently suggested by A. C. Sparavigna, concretely we use “freely available software” or local Sun radiation direction simulation computer programs. In this way we obtain and discuss pictures of the sunrise in the Lepenski Vir during winter and summer solstice and spring and autumn equinox in relation to position of the mountains, especially Treskavac (Trescovat) and Kukuvija at left (nearly east) Danube riverside (in Romania). While mountain Kukuvija represents really the marker for the Sun in date of the winter solstice, mountain Treskavac, in despite to usual opinions, does not represent a real marker for the Sun in date of the summer solstice. Sun rises behind Treskavac, roughly speaking, between 22.April and 1. May. It corresponds to year period when heliacal rising of the Pleiades constellation occurs, which by many ancient cultures, e.g. Celts of northern Europe, denotes very beginning of the year. All this, in common with some archeological facts (house-shrine No.47 in the Lepenski Vir holds seven signs beside hearth which would correspond to the seven Pleiades stars), opens a possibility that Lepenski Vir was an ancient Pleiades constellation observatory.

💡 Research Summary

The paper revisits the long‑standing debate over whether the Mesolithic settlement of Lepenski Vir (circa 9500–5500 BC) functioned primarily as a solar observatory or served a different astronomical purpose. Building on the methodology proposed by A. C. Sparavigna, the author employs freely available solar‑radiation simulation software to model sunrise azimuths for the winter solstice, summer solstice, and the two equinoxes as they would have appeared from the site. The simulated horizon is overlaid with the actual topography of the surrounding mountains, focusing especially on two prominent peaks: Kukuvija to the west (the “left” side of the Danube) and Treskavac to the east (the “right” side, in present‑day Romania).

The results show a clear alignment between Kukuvija and the winter‑solstice sunrise: on the day of the shortest daylight, the sun rises directly behind Kukuvija, providing a natural marker that could have been used by the inhabitants to signal the turning point of the year. In contrast, Treskavac does not correspond to the summer‑solstice sunrise. Instead, the simulation indicates that the sun rises behind Treskavac roughly between 22 April and 1 May. This period coincides with the heliacal rising of the Pleiades—a phenomenon that many ancient cultures, including the Celts of northern Europe, associated with the beginning of the agricultural year or the “new year.”

Archaeological evidence supports this reinterpretation. Within the settlement, House‑Shrine No. 47 contains a hearth flanked by seven distinct symbols, a number that matches the seven visible stars of the Pleiades cluster. Moreover, the orientation of the dwelling appears to be deliberately aligned east‑west, suggesting an intentional design to capture specific sunrise events. Together, these data points argue that Lepenski Vir may have been more than a simple solar calendar; it likely functioned as an observatory for the Pleiades, integrating stellar observations into the community’s seasonal rituals.

The author acknowledges several limitations. First, the digital reconstruction relies on modern topographic data, which may not perfectly reflect the landscape of the early Holocene due to erosion, river migration, and other geomorphological changes. Second, the assumption that prehistoric observers possessed the same visual acuity and conceptual framework as modern astronomers may oversimplify the cognitive context of the site. Third, the heliacal rising date of the Pleiades can vary with latitude and atmospheric conditions; the study adopts a generalized European timeframe without accounting for local variations.

Despite these caveats, the paper makes a compelling case for re‑evaluating Lepenski Vir’s astronomical role. By coupling precise solar‑position modeling with tangible archaeological markers, it demonstrates that the settlement’s builders likely recognized and encoded multiple celestial cycles—both solar and stellar—into their built environment. Future work that incorporates high‑resolution paleo‑topographic reconstructions and a broader range of stellar simulations could further test the hypothesis that Lepenski Vir served as an ancient Pleiades observatory, shedding new light on the sophistication of Mesolithic cosmology in the Danube basin.