In America, elements of what we now consider social studies (history, civics, geography) were taught in schools from the earliest days, but the formal emergence of "social studies" as a distinct, integrated discipline happened in the early 20th century. The Progressive Era (roughly 1890s-1920s) saw significant pushes for educational reform, and this period is when the field began to coalesce as a way to cultivate active and informed citizenship. The 1916 report of the Committee of Five of the American Historical Association is often cited as a key moment in this development.
In Europe, the timeline is similarly complex and varied across nations. While aspects of history, geography, and civics were taught earlier, the development of social studies as a unified subject was also a 20th-century phenomenon, influenced by similar progressive educational reforms, though the timing and specific approaches differed significantly across countries.
Therefore, there's no single year to pinpoint; instead, it's a gradual process spanning the early to mid-20th century in both America and Europe.