In late March 1857 a sepoy named Mangal Pandey attacked British officers at the military garrison in Barrackpore. He was arrested and then executed by the British in early April. Later in April sepoy troopers at Meerut refused the Enfield cartridges, and, as punishment, they were given long prison terms, fettered, and put in jail. This punishment incensed their comrades, who rose on May 10, shot their British officers, and marched to Delhi, where there were no European troops. There the local sepoy garrison joined the Meerut men, and by nightfall the aged pensionary Mughal emperor Bahādur Shah II had been nominally restored to power by a tumultuous soldiery. The seizure of Delhi provided a focus and set the pattern for the whole mutiny, which then spread throughout northern India. With the exception of the Mughal emperor and his sons and Nana Sahib, the adopted son of the deposed Maratha peshwa, none of the important Indian princes joined the mutineers.
Well the Syrian Civil War that is still going today. You could also say the Holocaust. Buddhist and Muslim conflicts in bangladesh. As well as the great awakening that swept across Britain and the US Colonies. The conversion of native americans to Christianity. Or my favorite the battle of Constantinople. That's just a few examples.