Agger (ancient Rome)

An agger (Latin) is an ancient Roman linear mound or embankment. The word is sometimes applied to fortifications, such as the Agger Servianus, a part of the Servian Wall of Rome, which protected the city on its most vulnerable side, the Campus Esquilinus. It consisted of a double rampart bearing formidable fortifications. In modern usage however, particularly in British archaeology, it is most commonly used to describe the ridge or embankment on which Roman roads were built. The course of a Roman road can often be traced today by the distinctive line of the agger across the landscape and even when destroyed by agriculture, the vestigial mound that can persist has allowed archaeologists in recent years to trace the course of many Roman roads using lidar.