In concluding this introductory chapter it may be well to Recapitulation. recapitulate the periods in Persian history of which we have spoken.

I.	The Indo-Íránian period.
II.	The early Íránian period.
III.	The period of Assyrian influence (B.C. 1000).1
IV.	The Medic period (B.C. 700).
V.	The Old Persian (Achæmenian) period (B.C. 550).
VI.	Interregnum, from the Invasion of Alexander to the Sásánian Restoration (B.C. 330—A.D. 226).
VII.	The Sásánian period (A.D. 226-652).
VIII.	The Muhammadan period, extending from the fall of the Sásánian Dynasty to the present day.

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It is with the last of these periods that we are principally concerned, and, as will in due time appear, it comprises numerous important subdivisions. Before approaching it, how­ever, something more remains to be said of the older Persian literature and its discovery, and sundry other matters germane thereto, which will be discussed in the next chapter.