This book is an intellectual and cultural history of a pivotal movement that broadly stamped nineteenth-century culture—namely, nationalist music. The nineteenth century is in many ways the century of “building nations,” and all across the European continent, nation building is incomprehensible without an understanding of the role that art played in it. This book examines the social and political functions of nationalist music to reveal how artists and their works transformed society, politics, and culture. As society was transformed in this process, so too was art, becoming a political tool for effecting social change. While in previous eras, art had indeed served various political functions, never before had art forms such as music been used to influence a mass audience to achieve extensive sociopolitical goals. There is another, final transformation I examine as well: composers became political activists, with distinct social and cultural agendas that they advanced in society through their works. The social, political, and intellectual story behind some of the great musical works of the time and the composers who created them is the focus of this book.