Final answer:
Islam began in the Arabian Peninsula and quickly expanded to form an empire larger than the Roman Empire.
Step-by-step explanation:
The correct answer is the Arabian Peninsula.
Islam began in the Arabian Peninsula in the early seventh century and quickly expanded its territory through military conquests. Within a hundred years, the Muslim army formed an empire larger than the Roman Empire up until that point. They conquered regions such as the Levant, Byzantine Egypt, North Africa, and even reached as far west as the Iberian Peninsula (modern-day Spain and Portugal).