Greek attitudes towards "barbarians" developed in parallel with the growth of chattel slavery – especially in Athens. Although the enslavement of Greeks for non-payment of debts continued in most Greek states, Athens banned this practice under Solon in the early 6th century BC. Under the Athenian democracy established ca. 508 BC, slavery came into use on a scale never before seen among the Greeks. Massive concentrations of slaves worked under especially brutal conditions in the silver mines at Laureion in south-eastern Attica after the discovery of a major vein of silver-bearing ore there in 483 BC, while the phenomenon of skilled slave craftsmen producing manufactured goods in small factories and workshops became increasingly common.