A medieval castle: why and how?

A feudal castle, why and how?
In the Middle Ages, a castle had three functions: it was a place of defense, a residence for the local lord and his family, and a symbol of power. The size and imposing appearance of a lord's castle enabled him to assert his power, particularly over his neighbors. The construction of such an edifice required a great deal of time and the services of a specialized, well-paid workforce. These craftsmen use machines, developed in medieval times, to make their work easier, not least for lifting. Local resources were also used for construction: wood and stone. In La Roche, this stone is schist, a stone with the particularity of splitting easily. It was coated with lime, giving the castle a white color that is hard to imagine today. The castle's roofs, meanwhile, were black and "peppered", i.e. conical.