This is the flag of the Kingdom of Mongolia. It comes from a world where China successfully repelled the Mongols early on. As a result, the Mongol Empire never came to be. The Mongols continued to be pushed farther and farther west until they arrived in Eastern Europe. Eventually, they settled around where Romania and southern Poland are in our world. Thus, the Kingdom of Mongolia was born. The Mongols were frequently visited by Byzantine missionaries, and the Mongolian Orthodox Church is the official state religion. The Byzantine Empire also remains a major trading partner for Mongolia. In more peculiar alliances, Mongolia is also a major ally of the tiny mountainous nation of Neo Hellas, the final remnant of pagan Greece.