665 Days In Iraq

In the 6th century BC, Cyrus the Great of neighbouring Persia defeated the Neo-Babylonian Empire at the Battle of Opis and Iraq was subsumed into the Achaemenid Empire for nearly four centuries. In the late 4th century BC, Alexander the Great conquered the region, putting it under Hellenistic Seleucid rule for nearly two centuries. The Parthians conquered the region during the reign of Mithridates I of Parthia (r. 171–138 BC). From Syria, the Romans invaded the region several times. The Sassanid Persians under Ardashir I destroyed the Parthian Empire and conquered the region in 224 AD. The region was thus a province of the Persian Empire for four centuries, until the Muslim conquest of Persia in the 7th century.
• Islamic Golden Age
The Islamic conquest in the 7th century established Islam in Iraq. Under the Rashidun Caliphate, the prophet Muhammad's cousin and son-in-law Ali moved his capital to Kufa "fi al-Iraq" when he became the fourth caliph. The Umayyad Caliphate ruled the province of Iraq from Damascus in the 7th century. (However, eventually there was a separate, independent Caliphate of Córdoba.)
The Abbasid Caliphate built the city of Baghdad in the 8th century as their capital, and it became the leading metropolis of the Arab and Muslim world for five centuries. Baghdad was the largest multicultural city of the Middle Ages, peaking at a population of more than a million, and was the centre of learning during the Islamic Golden Age. The Mongols destroyed the city during the siege of Baghdad in the 13th century.