What were the reasons behind Iran and Iraq splintering from what was previously Persia?

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Persia changed its name to Iran in 1935. Various invaders conquered the land known as Iraq, after Nebuchadnezzar's death, including Cyrus the Great in 539BC and Alexander the Great in 331BC. In the second century BC, it became part of the Persian Empire, remaining thus until the 7th century AD, when it was captured by Arab Muslims (Abbasids). The capital was moved to Baghdad which became an important commercial and cultural centre in the Middle Ages. Mongol invaders in AD1258 sacked Baghdad and murdered the Abbasid caliph. After much conflict over supremacy, the country was conquered by the Turks in the 17th century and became part of the Ottoman Empire. Turkish rule continued unchecked, and with very little development, until the end of the 19th century. Sep 03 02, 7:33 AM