at the mercy of
Observe that a physiological fact helps to account for the frequency and extent of the mutations which befell the nomad empires. Being accustomed to live in small communities, those who were temporarily united to form these realms generally retained a very marked spirit of independence.
A~ soon as a group larger than the tribal group was formed, authority rested on persuasion. That of Mahomet, as of all other chiefs, who, at a certain crisis, have assumed the command of considerable ethnic groups, was based on personal prestige and force, and on the power of eloquence, all of which are essentially personal and transitory factors.