The thesis examines the role of an American journalist of Irish descent, Januarius MacGahan, who became known as the “Liberator of Bulgaria.” Evidence presented in the thesis substantially restores MacGahan’s role in the liberation of Bulgaria from the Ottoman Empire. That accolade was deleted from Bulgarian history by Marxist revisionist historians during the Communist regimes in the 20th Century. This paper affirms that it was MacGahan’s resolve and passionate outcry against injustice and cruelty he witnessed, that changed the course of European diplomacy and ultimately led to a war that liberated Bulgaria.