Were the people in the Iron Age in Poland religious (PL)?

It is very difficult to reconstruct the beliefs of people back then on the base of what we found. Besides that, we can only imagine if religion was all pervasive or not that important. We think, the Iron Age people believed themselves to be surrounded by a world of ancestors, spirits and forces of nature. We find a lot of sun symbols, probably they used a sun chariot in their ceremonies. We find clay birds, but if these were ceremonial or children's toys is unclear. This counts as well for clay rattles. There are signs of cannibalism in the region of Biskupin in the Iron Age. The dead were usually cremated, sometimes with animals. The artefacts accompanying them make us think, they believed in an afterworld.