This article explores the use of modding as a formal tool for learning history. The article examines data from a formal analysis of Europa Universalis IV (EUIV), a survey of 331 EUIV forum participants and a case study of 18 university participants. Significant quantitative survey data indicated that 45% (149/331) of participants had modified EUIV, and of the 125 participants who responded with comments about modding, a significant number (86/125 responses or 68.8%) explained how they had learnt about history, geography or other subjects through the modding process. Closer analysis of survey and case study responses and mods reveals the variety of ways participants learnt and critiqued history through the modding process. The article discusses the data and the pedagogical affordance of modding in a few steps. First, the article briefly explores the evidence that indicates modding is popular within the EUIV gaming community. In this instance, it examines whether given the popularity of gaming practice, modding might also be seen as a new casual form of engagement with games. Second, the article reviews the modding process in EUIV and examines how both playing and creating mods may be beneficial for learning history. Modding is examined in terms of its pedagogical importance and the unique educational opportunities it may offer that are not otherwise accessible through other forms of game-based learning. Finally, the article explores how and what the case study participants learnt when they were tasked with creating and implementing playable mods to demonstrate their understanding of history. Overall, the article considers the growing importance of mods, how learners can create and represent history using mods and how mods can provide a platform for learners to develop their own critique and analysis of official history.