What happened on this land around c. 800–900 CE?

Rise of local Persianate dynasties, revival of Iranian culture and administration (New Persian language development).
Rulers
Abbasid Caliphate (nominal)
8th–9th centuries CE
Direct caliphal rule gradually gives way to powerful local dynasties (Taherids, Samanids, etc.)
Battles
Regional power struggles (e.g., local dynasts vs. caliphate)
c. 9th century
Military contests establish local Iranian dynasties.