The Ottomans also continue to challenge the Safavis for control of Azarbaijan and the Caucasus until the Treaty of Qasr-e Shirin in 1639 establishes frontiers in both Iraq and in the Caucasus that remain virtually unchanged.

The Safavi state reaches its apogee during the reign of Shah Abbas (1587-1629).

The shah gains breathing space to confront and defeat the Uzbeks by signing a largely disadvantageous treaty with the Ottomans.

He then fights successful campaigns against the Ottomans, reestablishing Iranian control over Iraq, Georgia, and parts of the Caucasus.

He counterbalances the power of the Qizilbash by creating a body of troops composed of enslaved Georgians and Armenians who are loyal to the person of the shah.

He extends state and crown lands and the provinces directly administered by the state, at the expense of the Qizilbash chiefs.

He relocates tribes to weaken their power, strengthens the bureaucracy, and further centralizes the administration.