Castles

Source A is useful for a historian studying castles. As it provides a visual representation of how big the castles were. It shows historians what the castles were made of. You also can find out what was inside the castles. 

Source B illustrates what the castles were for. Source B provides evidence that William of Normandy built castles to consolidate power. It also tells us that there are hundreds of motte and Baily castles in Europe. Lastly, it explains how castles developed over time.