The site of Kaptol Gradci from the older Iron Age (8th–5th century BC) holds global significance. The development of metallurgy and the use of iron influenced social changes, forming a ruling class of warriors and traders who, in the area from the Požega Valley to the southeastern Alpine region, shaped the cultural group known as Kaptol (8th–6th century BC).
At the location of Gradci, on the southern slopes of Papuk Mountain, above the present-day settlement of Kaptol, there was a fortified settlement and a burial ground under the tumuli. Kaptol was linked within a unique system of networks comprising smaller and larger settlements that served as crucial hubs for the transmission of ideas, goods and people.
The inhabitants of this area practiced cremation and buried their deceased under tumuli, burial mounds. This type of burial was primarily reserved for members of the elite class. In size and findings, tumulus 6 stood out, dating back to the late 8th or early 7th century BC. The findings indicated a rare double burial of warriors, which is associated with the concept of “brothers in arms,” as to what's depicted in the Iliad. These warriors fought and perished together; they weren't merely friends but possibly linked by blood relations. They belonged to the elite and exhibited a strongly emphasized heroic dimension.