With the philosophy and much of the sciences of the Greeks, Persians, and Indians at hand, the Muslims began gradually to bring into being the various intellectual perspectives which have dominated the horizon of Islamic civilization ever since. The schools of law and the Sufi brotherhoods became separately established in the third Islamic century, and the revelation which was until that time still close to its origin, and therefore in a state of ""fusion,"" became ""crystallised"" into its components. In a similar manner, the various intellectual perspectives, after several centuries, absorbed the nourishment provided by the vast heritage of the ancient world, already existing in Arabic, into the Islamic world view, and founded the diverse schools of philosophy and the arts and science. We can thereby legitimately refer to these schools as Muslim, since the concepts and formulations used by them were integrated into the Islamic view even if they originated elsewhere.""