"This is a Silver-grade armor found in a historic ruin in the Three Great Lakes region."
The Three Great Lakes region was further east of Leopoldine, where the great mountain range that prevented access to the sea to that state was located.
That was an ancient region where, thousands of years ago, some of the most powerful families of the time of the ten independent regions that existed before the formation of the empire were located.
However, with the victory of House Leopoldine against the Allied Army of the Ten Independent Regions, that area had been devastated thousands of years ago. At the time in question, such a place was abandoned, as it had no fertile soil, and with some consequences of the war, that area became home to high-level beasts.