Religious elements play a significant role in Russia's war of aggression against Ukraine. Russia has used religion to justify parts of the war that has been going on since 2014, the invasion of 24 February 2022 and its own war propaganda. In Ukraine, meanwhile, a church dispute continues that has concrete political and human rights implications, Islam plays an often overlooked role on both sides of the front, and the war in Russia also represents a paradigm shift for the security of Jewish life. This volume assembles contributions by authors from the fields of political science, ecumenics, theology, history, sociology, and ethics. All contributions are united by the basic assumption that although the Russian war of aggression against Ukraine is not a War of Religion, but it cannot be understood without considering and analysing the religious elements and contexts of justification.