Military expansion. The Rashidun Caliphate expanded gradually; within the span of 24 years of conquest, a vast territory was conquered comprising Mesopotamia, the Levant, parts of Anatolia, and most of the Sasanian Empire. Unlike the Sasanian Persians, the Byzantines, after losing Syria, retreated back to Anatolia.
1 And the nature of this reality again can neither be consistently represented as a fixed and hard substance nor as an unalterable something, but only as a fixed order of recurrence of continually changing events or impressions.
No, the word 'persistent' is an adjective, a word used to  describe a noun as stubbornly determined; as continuing to exist or  endure over a prolonged period (a persistent â¦condition, a  persistent salesman).    The noun form is persistence.