In the Roman Republic from 450 to 445 BCE, intermarriage of patricians and plebeians was banned. It was unpopular with the people and quickly lifted.
Over 400 years later, in 18 BCE, Emperor Augustus introduced a similar set of laws that were more widely accepted, and remained in place for centuries. The new laws limited some senatorial and equestrian individuals from marrying outside their rank. It also more generally limited marriages across class boundaries by limiting the marriage of Roman citizens with people who were registered as immoral – actors, adulterers, prostitutes, and those living off prostitution like pimps.
