Complex sentence: By the mid- 90s Persepolis and Esteghlal regained their dominant form and the league champions in the period of 1995-2001 was either Esteghlal or Persepolis.
Split into simpler sentences: By the mid- 90s Persepolis and Esteghlal regained their dominant form. The league championship every year between 1995-2001 was either Esteghlal or Persepolis.