The origins of International Conscientious Objectors Day can be traced back to the peace movements of the 20th century, particularly those that arose during and after World War I and World War II. During these global conflicts, many individuals refused to take up arms, believing that killing, even in the context of war, was morally unacceptable. These early objectors were often imprisoned, shunned, or even executed. Over time, peace organizations began advocating for their recognition, and May 15 eventually became the symbolic date to honor them globally.