Tithings were organised into groups of 10, called hundreds due to containing 100 hides; in modern times, these ancient hundreds still mostly retain their historic boundaries, despite each generally now containing vastly more than a mere 100 families. Each hundred was supervised by a constable, and groups of hundreds were combined to form shires, with each shire being under the control of an earl. Each unit had a court, and an officer to implement decisions of that court: the reeve. Thus different types of reeves were attested, including high-reeve, town-reeve, port-reeve, shire-reeve (predecessor to the sheriff), reeve of the hundred, and the reeve of a manor.