This chapter examines the presence of the police and policing from the classical world to the medieval. The Greek city states had no significant bodies of people organized specifically to ensure survival and welfare, though militias could be brought together to defend the state and suppress popular disorder. Some officials were charged with checking weights and measures and grain supplies. However, there were no institutions to prevent assaults and thefts, or to detect and pursue offenders. Both Ancient Greece and Ancient Rome were similar. Offences that affected the individual rather than the state were usually left to victims, their kin, or passers-by, if they were prepared to get involved. Victims, any servants that they had, their kin, or passers-by did not have to fight, though they sometimes did; but they could act as witnesses when a suspect was accused or brought before a court. Sources for police and policing in the classical world are thin, and much has to be gleaned from between the lines. Meanwhile, the sources for the medieval period are better, and, while these show the similar kinds of divisions and institutions, there are gaps in the sources and little to explore for those looking for police institutions.