How did ethnic and religious diversity shape Iraq’s history?

Iraq’s history has been profoundly shaped by its rich ethnic and religious diversity, which stems from the country’s creation after World War I by merging three distinct Ottoman Empire provinces: Mosul, Baghdad, and Basra.12

This mosaic of peoples—including Arabs, Kurds, and other groups—is further defined by the fundamental division within Islam between Sunni and Shiʿah communities. While these groups historically coexisted, fault lines deepened during the 20th century as authoritarian regimes exploited these tribal, sectarian, and ethnic divisions to maintain power.32

For decades, Sunni minorities dominated the military and civil service, marginalizing the Shiʿah majority and Kurdish populations. The Baʿathist regime further exacerbated these tensions through forced relocations, ethnic homogenization, and the suppression of political participation. Following the transition to elective government, these historical divisions have continued to influence political stability, often resulting in factional stalemates and sectarian conflict as various groups compete for control over state institutions and resources.456