The value of the goal lies in the goal itself; and therefore the goal cannot be attained unless it is pursued for its own sake. - Arnold J. Toynbee

As the Macedonian conquest, by breaking up the Achaemenian Empire (i.e. the Persian Empire of Cyrus and his successors), prepared the soil for the seed of Hellenism, so the Arab conquest opened the way for the Umayyads, and after them the 'Abbasids, to reconstruct a universal state which was the equivalent of the Achaemenian Empire.

If we take the antiquity of Man to be something like 300,000 years, then the antiquity of civilizations, so far from being coeval with human history, will be found to cover less than 2 percent of its present span: less than 6,000 years out of 300,000 . On this time-scale , the lives of our twenty-one civilizations-distributed over not more than three generations of societies and concentrated within less than one-fiftieth part of the lifetime of Mankind- must be regarded, on a philosophic view, as contemporary with one another.

A life which does not go into action is a failure.