In ancient Rome, any member of a group of citizen families who, in contrast to the plebeians, formed a privileged nobility. They attempted to hold on to magistracies, priesthoods, and legal and religious knowledge, and the great civil struggle of the Roman republic was the effort of the plebeians to achieve equality and break the patrician monopoly. Gradually the patricians lost their monopolyexcept in a few areas, such as selected priesthoods and the office of interrexand in the late republic (1st century BC) the distinction lost political importance. After 27 BC, patrician rank was necessary for ascent to the imperial throne. After Constantine's reign (AD 337), the term became an honorary title with no particular power.