A more thorough explanation:

De perambulatione facienda is a Latin term used in law that means "for making perambulation." It refers to a writ that orders the sheriff to go with 12 knights of the county to settle a boundary dispute by walking about to determine the proper boundary between adjacent towns or lordships.

An example of de perambulatione facienda would be if two neighboring towns were arguing over where their boundary line was. The court would issue a writ to the sheriff, ordering them to gather 12 knights from the county to walk the boundary line and determine the proper boundary between the two towns.

Another example would be if two lordships were disputing the location of their boundary. The court would issue a writ to the sheriff, ordering them to gather 12 knights to walk the boundary line and determine the proper boundary between the two lordships.

These examples illustrate how de perambulatione facienda was used in medieval times to settle boundary disputes between neighboring towns or lordships. The process of walking the boundary line with 12 knights was seen as a fair and impartial way to determine the proper boundary, and it was often used in cases where there was no clear evidence to support one side or the other.