The history of Mozhaysk is rooted in the depths of time, when these lands were the borderlands between Slavic and Baltic tribes. The city was first mentioned in Russian chronicles under the year 1231. Initially, it was part of the Principality of Smolensk, but even then, it played a notable role due to its location. According to researchers, the city's name comes from a hydronym—the small Mozhayka River, which in Baltic dialects may mean "small" or "marshy."
The transformation of a small settlement into a significant city was driven by several key factors. The city was established on a high hill, naturally protected by the river and ravines, making it an ideal location for a fortress. At the beginning of the 14th century, Mozhaysk was annexed to the Principality of Moscow, becoming its most vital western outpost—the "Holy City of the Russians," protecting the approaches to Moscow. Furthermore, its location at the headwaters of the Moskva River allowed for control over water and land trade routes connecting central Russia with western lands.
From its founding, Mozhaysk developed as both a fortress city and a spiritual center. Early on, a unique cult of Saint Nicholas of Mozhaysk formed here—the patron saint of the city, traditionally depicted with a sword in one hand and a church in the other. The economy of the early city relied on servicing the prince's retinue, the development of blacksmithing, and trade. Crafts necessary for defense flourished here, and many wooden (and later stone) churches were built, attracting pilgrims and contributing to the city's prosperity.