In AD 77, Roman forces under Agricola marched into the northern reaches of Britain in an attempt to pacify the Caledonian tribesman. For seven years, the Romans marched and battled across what is now Scotland. Finally, in AD 83, they fought the final battle at Mons Graupius where 10,000 Caledonians were slaughtered from only 360 Roman dead. It proved the high-water mark of Roman power in Britain. Following unrest elsewhere in the empire, the north of Scotland was abandoned and Rome's forces began their long retreat. Never again would Roman arms stand on the edge of the known world.