Archaeologists excavating an Iron Age settlement in central Poland have uncovered the remains of a 2,500-year-old longhouse alongside an exceptionally rare ancient coin, offering new evidence of contacts between communities in what is now Poland and peoples living nearly 1,500 kilometres away.
The discoveries were made at the Łysa Góra archaeological site in the Chorzele commune of Mazovia, where researchers from the State Archaeological Museum in Warsaw have been conducting excavations for the past three seasons.
The site is associated with the West Baltic Barrow Culture, an Iron Age society that inhabited parts of what are now north-eastern Poland and neighbouring regions. Recent excavations have revealed growing evidence of Celtic influence at the settlement.
Among this season’s most striking finds is a bronze coin minted during the reign of Seuthes III, ruler of the ancient Odrysian kingdom of Thrace, between 323 and 316 BC.
The coin, more than 2,300 years old, is believed to be the oldest coin yet recovered from a documented archaeological excavation in Poland.
One side depicts a horseman accompanied by a mint mark, while the other bears an image of Zeus wearing a laurel wreath. Archaeologists also found that the coin had been pierced and that the hole showed signs of wear, suggesting it was carried on a cord or strap and worn as a pendant rather than simply used as currency.
It was minted at Seuthopolis, the ancient Thracian capital located near present-day Kazanlak in Bulgaria — almost 1,500 kilometres from Łysa Góra as the crow flies.
The extraordinary distance between the two locations provides evidence of long-range connections linking Iron Age communities in Mazovia with south-eastern Europe.
Researchers believe the coin may have reached Łysa Góra through Celtic groups. Seuthopolis was attacked by Celts during the first half of the third century BC, and archaeologists have raised the possibility that the object was brought north by someone connected with those incursions.
It may even have been kept as a personal souvenir and subsequently worn around the neck.
The find could be one of several ancient coins at the settlement. Dr Bartłomiej Kaczyński of the State Archaeological Museum said two additional objects recovered during the excavations may be Greek obols, although specialists have yet to confirm their identification.
A 17-Metre Iron Age Home
The coins were not the only major discovery made during this year’s excavations.
Archaeologists also identified the remains of a substantial timber longhouse measuring about 17.5 metres in length and four metres in width. Features uncovered in 2025 had initially been interpreted as a possible defensive structure or ritual ditch, but further excavation revealed that they formed part of a building.
The structure appears to have been divided into individual residential sections measuring roughly four by five metres.
“This is a revelation for us,” Dr Kaczyński said, describing the building as a longhouse comparable in its arrangement to structures known from the famous prehistoric settlement at Biskupin.
The discovery is particularly significant because it allows archaeologists to build a much clearer picture of how the community at Łysa Góra lived.
The longhouse is thought to have been constructed by members of the West Baltic Barrow Culture around the fifth century BC, making it approximately 2,500 years old.
Although comparable buildings are relatively well known from south-western Poland, Dr Kaczyński said this form of construction is highly unusual in Mazovia and north-eastern Poland.
Its presence at Łysa Góra therefore adds an important new dimension to archaeologists’ understanding of Iron Age settlement patterns in the region.
Celtic Connections at Łysa Góra
The latest discoveries add to a growing collection of remarkable artefacts from the site.
Previous excavations produced a rare Celtic helmet dating to the fourth century BC as well as an instrument believed to have been used for trepanation — the surgical practice of making an opening in the skull.
Taken together with the Thracian coin and possible Greek obols, the finds suggest that Łysa Góra was connected to cultural and exchange networks extending far beyond the immediate region.
The most important artefacts are now undergoing conservation at the State Archaeological Museum.
Plans are being made to display the discoveries in an exhibition devoted to Łysa Góra in two years’ time, marking the museum’s centenary. The ancient coin, Celtic helmet and trepanation tools are expected to be among its centrepieces.
Archaeological investigations at Łysa Góra first took place during the 1970s and 1980s. Researchers returned in 2024 as part of preparations for an educational trail at the site, requiring new surveys and measures to protect the archaeological remains from potential damage.
Those investigations have since transformed understanding of the settlement — and archaeologists believe further surprises may still be buried beneath Łysa Góra.
Header Image Credit : B. Kaczyński
Sources : PAP