It really bugs me when religious go on about the murders atheists have carried out saying they account for far more than religious murders.
Here is an incomplete list of wars or conflicts in which one side or both were fighting in the name of religion.
Albigensian Crusade, 1208-49
Algeria, 1992-
Baha'is, 1848-54
Bosnia, 1992-95
Boxer Rebellion, 1899-1901
Christian Romans, 30-313 CE
Croatia, 1991-92
English Civil War, 1642-46
Holocaust, 1938-45
Huguenot Wars, 1562-1598
India, 1992-2002
India: Suttee & Thugs
Indo-Pakistani Partition, 1947
Iran, Islamic Republic, 1979-
Iraq, Shiites, 1991-92
Jews, 1348
Jonestown, 1978
Lebanon 1860 / 1975-92
Molucca Is., 1999-
Mongolia, 1937-39
Northern Ireland, 1974-98
Russian pogroms 1905-06 / 1917-22
St. Bartholemew Massacre, 1572
Shang China, ca. 1300-1050 BCE
Shimabara Revolt, Japan 1637-38
Sikh uprising, India, 1984-91
Spanish Inquisition, 1478-1834
Taiping Rebellion, 1850-64
Thirty Years War, 1618-48
Tudor England
Vietnam, 1800s
Witch Hunts, 1400-1800
Xhosa, 1857
Arab Outbreak, 7th Century CE
Arab-Israeli Wars, 1948-
Al Qaeda, 1993-
Crusades, 1095-1291
Dutch Revolt, 1566-1609
Nigeria, 1990s, 2000s
These account for in excess of 800,000,000 deaths in the name of religion, beat that atheists.
Note the list does not included those killed by Hitler (catholic) or Stalin (Georgian Orthodox Christian) both murdered for nationalistic reasons, not religious