#Roman castrum

• Agger — An earthen rampart, embankment, dyke, or artificial fortification raised in antiquity, particularly by the Roman army, to protect a military camp (castrum) or to serve as an assault ramp during city sieges. It represents a compact defensive or offensive structure built by the orderly accumulation of earth, stones, and logs.
• Amutria — The name of an ancient Geto-Dacian settlement and subsequent Roman castrum, mentioned by the geographer Claudius Ptolemy in his work Geographia and historically located in the Oltenia region, along the Jiu River valley or the Danubian route. It represents a nodal point of archaeological interest for studying the fortification network of Dacia Malvensis and Daco-Roman continuity in the Carpatho-Danubian basin.
• Arrubium — The ancient designation of a Roman castrum and fortified civil settlement situated in the province of Moesia Inferior, archaeologically located on the current territory of Măcin town in Tulcea County, Romania. The fortified site held an essential strategic role within the Danubian limes defensive network, securing fluvial traffic monitoring and the imperial border's protection against trans-Danubian migratory incursions.
• Arutela — The name of a Roman castrum and fortified civilian settlement in Dacia Inferior, located on the left bank of the Olt River near the Cozia Monastery in Vâlcea County. This archaeologically significant national site was structurally built by Syrian archers during Emperor Hadrian's reign as part of the Limes Alutanus defensive line, and was partially destroyed by the river's changing course.