What notable architectural feature of the Hagia Sophia showcases the influence of earlier Roman architecture?

The notable architectural feature of the Hagia Sophia that showcases the influence of earlier Roman architecture is the use of a large dome supported by pendentives. This innovative design allowed architects to create a vast, open interior space, which was a hallmark of Roman engineering. The dome itself, resting on a square base through the use of pendentives, enabled a seamless transition between the circular dome and the rectangular space below, demonstrating advanced architectural techniques derived from Roman precedents.

This reflects how Byzantine architecture drew heavily from Roman ideas, particularly in the use of domes and complex structural forms to create grand and awe-inspiring interiors that emphasized not just functional space but also religious significance. The mastery of the dome in the Hagia Sophia influenced many later buildings and marked a significant transition in architectural practices from the Roman to Byzantine eras.