Final answer:
The Rashidun Caliphate conquered the Byzantine Empire after the death of Muhammad.
Step-by-step explanation:
The empire conquered by the Rashidun Caliphate after the death of Muhammad was the Byzantine Empire. The Rashidun Caliphate, the first Islamic caliphate, launched military campaigns against the Byzantine Empire in the early 7th century. These campaigns eventually led to the conquest of major Byzantine territories, including Egypt, Syria, and parts of Anatolia.
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