A more thorough explanation:

Definition: A counter-roll is a historical record that is maintained by an officer to verify the accuracy of another officer's record. This is particularly true for the rolls kept by a sheriff and a coroner.

Example: In medieval England, the sheriff was responsible for maintaining a roll of all the people in his jurisdiction who were eligible for military service. This roll was called the muster roll. The coroner, on the other hand, was responsible for maintaining a roll of all the deaths that occurred in his jurisdiction. This roll was called the death roll. To ensure that both rolls were accurate, the sheriff and the coroner would keep a counter-roll, which was a duplicate of the other officer's roll. This way, they could compare the two rolls and make sure that they matched.

Explanation: The example illustrates how a counter-roll was used in medieval England to ensure the accuracy of the muster roll and the death roll. By keeping a duplicate of the other officer's roll, the sheriff and the coroner could compare the two rolls and make sure that they matched. This helped to prevent errors and fraud, and ensured that the records were reliable.