Many architects were famous for their craft, and Gundulf was one of the most famous. He eventually became a bishop of Rochester and created buildings all around Europe, including the famous Rochester Cathedral.
Castle designs changed from Romanesque styles to Gothic styles through the Middle Ages. There were many famous architects, especially ones who worked for William the Conquerors
Such as Robert de Bellême who was a military architect and eventually the chief architect for William
Romanesque architecture was popular after the fall of Rome, as the Gothic architecture was popular during the later medieval times. Gothic architecture pointed arches, and took light into consideration with flying buttresses.
Also called Norman Architecture, was wildly popular after the dark ages, and were usually dark, and built with very large arches. Arches are very stable structures, and during the medieval times, architects took ideas from the advanced Roman architecture to build beautiful and functional structures.