Since the legions were officially open only to Roman citizens, Max Cary and Howard Hayes Scullard argue that at least in some provinces at this time "many provincials must have been recruited who lacked any genuine claim to Roman citizenship but received it unofficially on enlistment," a practice that was to increase in the 2nd century. This is most likely in those provinces where the pool of Roman citizens was not large enough to fulfill the provincial army's recruitment needs. One possible example is Britain, where one estimate puts the citizen pool in the 1st century at only 50,000 out of a total provincial population of around two million.