when the conditions have been hostile it is not noticeable at the first
glance but in reality has been of great consequence. The causes of this
are very complicated. And it is necessary on account of its universal
value to examine a wide concatenation of facts. But from a general point
of view there is no doubt that it has its roots principally in the
continuity of the historical and cultural traditions. Particular
significance attaches to the circumstance that just in the epoch
preceding the Arab conquest Persia had experienced a period of national
revival after the horrors that its sovereignty had undergone, at the
hands, for instance, of Alexander the Great.[1] Therefore for the study
of Iranian tradition in Islam the period of the Sasanian dynasty
preceding the Arab conquest has a special significance.

[Footnote 1: This is explained by the hatred given expression to in the
Parsi tradition regarding Alexander. Comp. J. Darmesteter _La Legende de
Alexandre chez les Parses. Essais Orientaux_, Paris 1883, pp. 227-251.]

The Sasanian dynasty issuing from a small principality in the south of
Persia--a principality which, properly speaking bears the title of the
"kernel of the Persian nation"--occupies a considerable position in
Persian history. Wide imperial aims were united with a plenitude of
solid organisation of government so perfect that it passed into a
proverb among the Arabs. In this last connection the Sasanian tradition
survived for a long time a number of Moslem dynasties. The powerful
influence which Iranian tradition exercised was felt by the Abbaside
Khahlifs and after them by the Turkish Seljuks. But not only the science
of government, a good deal of other matters of cultural and historical
importance in the latter times have their explanation in the Sasanian
epoch. Placed on the confines of the Greco-Roman world on the one hand,
and China and India on the other, Sasanian Persia served during the