The existence of a mysterious hillfort on an island near the Hepner family's palace in Jankowo was known since at least the latter half of the 19th century – the first report of this discovery appeared in 1882 in the German journal "Zeitschrift für Ethnologie". Four years later, during routine earthworks on the island, a certain Pahlke – an estate manager and archaeology enthusiast, conducted initial investigations. Over the following years, continued by his successor Schwartz, various intriguing finds were uncovered, including a controversial, World War II-lost artifact – the deity head from Jankowo.
Pahlke discovered that the island's center featured a mound encircled by a rampart, and a closer examination of its cross-section revealed it was composed of two layers, the lower containing numerous traces of burning. Further scrutiny of the island also yielded interesting results. On its edges, numerous logs, likely intended for fuel, were found, and on the eastern shore, a breakwater constructed of diagonally driven stakes was unearthed. Undoubtedly, an organized community once lived on the island.
The discovery of an ancient settlement in Biskupin, some 40 km away, significantly boosted interest in the Jankowskie hillfort in the interwar years. By then, Jankowo had begun to feature in scholarly literature, in works discussing both Lusatian and medieval forts.
However, the first professional attempts to determine the site's chronology were only undertaken in 1960, during research led by the State Archaeological Museum in Warsaw's Excavation Expedition. Further exploratory work occurred six years later, but comprehensive excavations were conducted on the island between 1969-72 by the Department of Archaeology of Greater Poland and Pomerania of the Institute of the History of Material Culture, Polish Academy of Sciences. These were the last investigations on the island, which was almost entirely submerged a few years later due to the construction of a dam on Lake Pakoskie. Thanks to these excavations, it was finally established that the hillfort on the island developed in two stages, with its peak during the Hallstatt C and D periods (7th-5th century BC), when it was inhabited by the Lusatian culture, and during the early Middle Ages (7th-8th century AD). The earliest signs of settlement date back to the late Neolithic (2500-1700 BC).
One of the most intriguing discoveries associated with the medieval fort on Lake Pakoskie is the so-called Jankowo head, a human head carved in oak wood. This artifact was unearthed in 1887 while deepening a canal at the island's edge, found in the silted lakebed at a depth of two meters. The head was 24 cm tall, with a quadrangular indentation at its base.
The estate manager of Jankowo, who was also an amateur archaeologist, Pahlke, cleaned the find, filled it with putty, and preserved it with salicylic acid. He then documented and sent its details to the German historical society in Poznań. Consequently, the head ended up in the Poznań Archaeological Museum, where it was examined by Kurt Langenheim, a German historian and archaeologist specializing in Viking matters.
From his examination, he theorized that the head was carved by Vikings (or a Scandinavian artist), and detailed his observations and conclusions in a 1944 article titled "Der Kopf von Adolfinenhof Kreis Mogilno, eine Wikingische Holzplastik". This theory was later linked with a nationalist theory of pre-Germanic settlement in the area, later displaced by the arriving Slavs. This theory aimed to support Hitler's Germany's territorial claims.
Unfortunately, Langenheim's theory could never be verified, as the Jankowo sculpture was lost at the end of World War II. Rumors even emerged that the German researcher himself looted it from the museum. Fortunately, photographs and documentation of the sculpture survived, allowing for several other theories to be formulated.
For instance, the Jankowo sculpture was linked with the Celts. Janina Rosen-Przeworska, an expert in this field, connected the head with the Celtic motif of "severed heads" and the traces of a Celtic sanctuary discovered nearby in Janikowo. Christian interpretations also emerged – some historians believed the head was part of a sculpture of the Crucified Christ.
Today, most historians attribute Slavic origins to the sculpture, but determining its function and time of creation remains a challenge. An interesting theory is proposed by Anna Błażejewska, who believes the head was created at the earliest at the turn of the 10th and 11th centuries, during the Christianization of Polish lands, and was inspired by Christian Ottonian art, but depicted a pagan deity.
The head is distinguished from other sculptures in the area by its detailed facial work and anthropocentric convention, combined with conventional treatment of the sides and back (leading to its attribution to prehistoric artistic tradition). According to Błażejewska, the significant detail and the character of the sculpture's craftsmanship, clearly influenced by Ottonian plastic art, attest to this.
Jankowo is located near Kruszwica, which in the 11th century was one of the major centers of early feudal power, and thus a place of intense artistic activity, also inspired by Ottonian art. Hence, it is possible that the Jankowski sculptor was influenced by the solutions of Kruszwica artists and applied them in his work. He might even have encountered original Ottonian art – it was common for missionaries to bring artists to Christianized areas.
Despite clear connotations with Christian art, Błażejewska believes the sculpture represents a pagan deity. This is indicated by its discovery site: the bottom of a lake, into which the head was likely thrown. It seems unlikely that a sculpture of Christ would be treated this way during Christianization. At the same time, no sacral artifact in the nearby vicinity has been linked to the sculpture.
So, why did the Jankowski artist opt for new means of expression to depict an old form of worship? Perhaps he was aware that this was the only way to counter the encroaching Christianization with traditional beliefs. Comparing the style and form of the head with other Ottonian artifacts suggests it was likely created in the 1030s, during the pagan reaction in these lands. According to Błażejewska, the head might have been destroyed during intertribal conflicts, and its disposal in the lake could signify its desecration. It certainly wasn't destroyed later than the end of the 11th century, when the fall of the Jankowski fort and the complete disappearance of the settlement on the island occurred.