Why were Arabs successful?

only one possible explanation remains for the Arab success-and that was the spirit of Islam... The generous terms that the invading armies usually offered made their faith accessible to the conquered populations. ... Simply put, Islam may have sped the conquests, but it also showed much greater staying power.

the treaty of brest-litovsk was a peace treaty signed on 3 march 1918 between the new bolshevik government of russia and the central powers (german empire, austria-hungary, bulgaria, and the ottoman empire), that ended russia's participation in world war i.

that was the type of government the spanish colonists were used to.