Early modern European warfare features prominently in several important discussions of early modern violence, notably the debate on the Military Revolution and its variants, as well as forming part of the standard narrative of state formation and the emergence of an international order based on sovereign states. While the dominant trend was towards establishing the state as a monopoly of legitimate violence, the patterns and practices of European warfare remained diverse, as were the ways in which they interacted with state and ‘international’ structures. The creation of permanent forces was slow and uneven, while their implications varied depending on whether they were navies or armies. This chapter contests conventional conceptual models, such as that of ‘limited war’ waged by allegedly disinterested ‘mercenaries’. It argues that efforts to impose tighter discipline arose from multiple political, cultural, social and religious impulses, and varied in effectiveness. War was certainly not limited in terms of its capacity for violence and destruction, but it nonetheless remained broadly within established Christian concepts of ‘just war’ directed by a ‘proper authority’ for legitimate ends. The risks inherent in military operations were an additional constraining factor, despite this period becoming known as an ‘age of battles’.