Oliver Hazard Perry,I believe.
Answer: They feared the empire had become too large to defend efficiently.
Answer:
Abu Bakr was an adviser and companion of the Prophet Muhammad. Abu Abu Bakr controlled the administration and later selected as caliph (ruler of the Islam community) after Muhammad's death. As a caliph, Abu Bakr launched many military campaigns to bring Arabia under Islam and was successful in expanding Islam further through conquering.
