Before the county of Corvis, there was the Wizard Corvus. Thirteen hundred years ago, a mad powerful wizard had an estate in the area that became the county of Corvis. Over his 800 year span, he created thousands of magikal items of various types and power level, some of which survive to this day.
"...the city was built on many levels, linked by stone bridges. But with the improvements in diet and corresponding increase in stature and strength of the populace, these bridges became too low, and the people would hit their heads. The bridges were eventually done away with in 1764, but the scars on the walls where they once jutted out remain, and in Low Bridge Street there is still one extant bridge, measuring about 6' high." - Chronicler Rasill, Mondopedia, Vol II (The Lands of Hyellia)