A man who was inspecting geothermal pipes in Salo, Finland, unwittingly uncovered a Christian cemetery dating back a thousand years to the time of the Swedish Crusades.

The first discovery came in August, after days of heavy rain, when the local landowner spotted a shaft of iron sticking out of the ground. It turned out to be a 12th-century sword with a cross-guard and a three-sided knob, known as a pommel.

The landowner contacted an archeologist at the University of Turku who investigated the site alongside another archaeologist from the Turku Museum Center, responsible for assembling and conserving the region’s cultural heritage. Believing the sword was not an isolated object, the researchers began excavating the site in September with a team of archaeology students.

Crusader-era sword and part of the scabbard found in a geothermal pipe trench. Photo: Riikka Saarinen / Turku Museum Center.

Their hunch was correct. The team found human bones, remnants of clothes, and parts of a wooden coffin. Most remarkable, however, was a partially intact leather belt with 30 bronze rings and animal head buckles. The belt was still attached to a sheath decorated with bronze rings. Finding textiles dating back a millennium is extremely rare with researchers saying the last time a similar discovery was made in Finland was in the 1950s.

Though the initial finds all belonged to a single grave, the archaeologists soon found a further eight burial sites. They believe this is part of a much larger site, one containing possibly hundreds of graves.

One of the rosette-patterned bronze ornaments belonging to the belt. Photo: Juha Ruohonen / University of Turku, archaeology.

“The observation can be considered very significant from a research point of view, as mortuary cemeteries from the time of the Crusades are clearly less known in Finland than cremation cemeteries,” the authors wrote in a statement explaining the discovery. “So far, this is also the only confirmed burial dating to the end of the Iron Age from the Salo or Uskelanjoki valley.”

The site abuts a medieval stone church that was built in the 15th century. The burials discovered seem to follow Christian customs which leads researchers to believe there was an earlier church that preceded the present one by several hundred years.

The grave pattern on the wall of the pipe trench. Photo Juha Ruohonen / University of Turku, archaeology.

Researchers will now conduct extensive studies on the artifacts found in the cemetery including x-rays and radiocarbon dating.

The Swedish Crusades were a series of campaigns launched between the 12th and 13th centuries that saw the Catholic Church and Sweden attempt to convert pagan Finns to Christianity.