Many socio-economic changes occurred in southern Europe during the first millennium BC. In north-eastern Iberia societies evolved from the small-scale local groups of the Late Bronze Age to the more complex societies of the Iron Age. Together with a diversity of material changes (detected in pottery, agricultural techniques, architecture, etc.), a new ritual manifestation is attested in the Ancient Iberian Period (about 550 BC), lasting until some time after the Roman conquest. This consisted of sheep and goats (among other species) being carefully deposited below the floors of some domestic buildings. In this article the characteristics of these associated bone groups are described and their significance is discussed.