The use of gaming technologies in education holds great promise to provide engaging learning experiences. Whereas video games have been successfully used to foster learning in several school subjects, the current understanding of the potential of video games for history learning is still limited. This paper details the development of Limes, a 2D top-down educational game created in Unity and rendered in pixel art. The game targets 5th/6th grade secondary school students and is set in the third century AD in southern Germany, a period characterized by political and social instabilities. Limes digs into the complex relations between the Roman Empire and the Alemanni tribe, one of the most powerful Germanic tribes of this period. The player can experience this pixelated world through the eyes of an Alemanni child, who forms a friendship with a Roman centurion. The unfolding narrative places the young protagonist in the precarious balance of peace and conflict, and the player needs to navigate the diplomatic tensions of the era. The gameplay consists of five levels, including primary missions and optional secondary missions which unlock special features (e.g., puzzles, quizzes). Limes incorporates a variety of game mechanics, ranging from running and interacting with characters to stealth missions, throwing rocks, and horse racing. These dynamics are integrated into the historical narrative of the game, enriching the player's experience. The game development process combined insights and methods from multiple disciplines, including game-based learning, educational, social, and cultural psychology, education sciences and pedagogy, and history education. Moreover, the game capitalizes on Unity’s wide array of development tools, which provide extensive customization possibilities, and employs pixel art, facilitating an engaging environment while maintaining a cost-conscious development process. Initial tests and expert feedback highlight the promise of Limes as a game that leverages historical accuracy and innovative educational tools to foster a deeper understanding of Roman history. Next steps include empirical studies with students to test the game's effectiveness (e.g., in improving interest in and knowledge of Roman history).