And yet for several centuries this form of Gothic architecture was the highest expression of the sincere feeling for art which inspired the whole northern continent. From a previous chapter, you will remember how the people of the late Middle Ages lived. Unless they were peasants and dwelt in villages, they were citizens of a "city" or "civitas," the old Latin name for a tribe. And indeed, behind their high walls and their deep moats, these good burghers were true tribesmen who shared the common dangers and enjoyed the common safety and prosperity which they derived from their system of mutual protection.