Police
Law enforcement, however, constitutes only part of policing activity. Policing has included an array of activities in different situations, but the predominant ones are concerned with the preservation of order. In some societies, in the late 18th and early 19th centuries, these developed within the context of maintaining the class system and the protection of private property. Many police forces suffer from police corruption to a greater or lesser degree. The police force is usually a public sector service, meaning they are paid through taxes.

Q: When were police used to protect the class system?
late 18th and early 19th centuries