While many of these empires referred to themselves as Persian, they were often ruled by ethnic Medes, Babylonians, or Parthians. Iranian dynastic history was interrupted by the Arab conquest of Persia in 651 AD, establishing the even larger Islamic caliphate, and later by the Mongol invasion.
The main religion of ancient Persia was the native Zoroastrianism, but after the seventh century, it was replaced by Islam.
The Safavid Empire was the first Persian empire established after Arab conquest of Persia by Shah Ismail I. From their base in Ardabil, the Safavid Persians established control over parts of Greater Iran and reasserted the Iranian identity of the region, thus becoming the first native dynasty since the Sasanian Empire to establish a unified Iranian state.