The First Sudanese Civil War lasted from 1955 to 1972, primarily between the northern and southern regions of Sudan. The conflict arose due to political, economic, and cultural disparities, with the north predominantly Muslim and Arab, while the south was largely Christian and African. Tensions escalated after Sudan gained independence from British-Egyptian rule in 1956, leading to armed resistance in the south. The war resulted in significant loss of life and displacement, with an estimated 500,000 casualties. It ended with the Addis Ababa Agreement in 1972, which granted the south autonomy, but underlying issues remained unresolved, setting the stage for future conflicts.