It was the great achievement of the Byzantine architects Isidorus and Anthemius , to transfer the weight of the dome to the pillars using arches and pendentives , the four triangular sections of masonry that fill the gaps between arches and dome , to create the illusion of an unsupported dome floating in space .
Isidorus and Anthemius made the dome look like it was floating in space by using arches and pendentives to support it .