Centuries before being included in Hugo Grotius’s De iure belli ac pacis and De iure praedae, the subject of reprisal was already being discussed in medieval literature. The aim of this paper is to examine the medieval and early modern practice and theory of reprisal as it developed before and during Grotius’s lifetime. Its first part investigates a number of important foundational elements, such as the issues of definition and terminology, and the common characteristics of a reprisal case. In the second half, the author explores why reprisals were deemed to be a ‘perversus mos’ or ‘bad custom’ and how continued reliance on this practice was nonetheless justified by inserting it into the medieval just war doctrine. The paper does not provide a systematic study of Grotius’s own engagement with medieval reprisal sources. Rather, it should be read in conjunction with another publication in this same volume, ‘Grotius on Reprisal’ by Randall Lesaffer.

雨果·格罗蒂乌斯（Hugo Grotius）的《De iure belli ac pacis》和《De iure praedae》之前的世纪报复的主题已经在中世纪文学中讨论过了。本文的目的是研究格罗蒂乌斯一生之前和期间发展起来的中世纪和早期现代报复理论。第一部分研究了许多重要的基本要素，例如定义和术语问题以及报复案件的共同特征。在下半部分，作者探讨了为什么报复被视为“反常的习俗”或“坏习惯”，以及如何通过将其引入中世纪的正义战争学说来证明继续依赖这种做法是合理的。本文没有对Grotius自己对中世纪报复来源的参与进行系统的研究。而是应与同一卷中的另一本出版物一起阅读，