Five centuries of incumbent Hispano-Roman urban culture gave way to interaction with the nomadic, pastoralist lifestyles of tribes such as the Alans (dominant in much of former Lusitania after the Battle of Mérida). Roman imperial law-and-order succumbed to the looser hierarchies - based on blood and tribal allegiances - of the invaders from the north. War, slave-raids, banditry, religious intolerance, apartheid - the Visigoths applied a 'no mixing' policy for much of their rule - all led to economic decline across Iberia.