This open access book introduces the concept of Internally Displaced Persons (IDPs) into early modern migration history, arguing that the current characterisation of early modern refugee movements is oversimplified. During this period, hundreds of thousands of people fled Europe s religious wars, seeking asylum in neighbouring states or across the seas. The efforts and trials of these refugees have been chartered and analysed by many prominent scholars, who have demonstrated the movements entanglement with the state formation process and the rise of humanitarianism. As a result, early modern refugees are frequently grouped together under the umbrella term religious refugees , contrasting them with present-day refugees, which are identified in terms of national or ethnic belonging. However, as this book demonstrates, there were considerable differences among the forced migrants, and one of the most significant was that whereas some of them fled outside of established political relationships, many of them moved within such bonds and borders. As today, early modern forced migration was multifaceted and encompassed diverse groups with diverse needs and motives. To address that complexity, the author highlights the necessity of differentiating between these various groups of migrants and determining what factors influenced reception and rejection practices, both locally and centrally, while acknowledging that many factors often coincided.