IS-LE would like to call your attention to this article “Eastern Europe in the Middle Ages: What, Where, When”: https://www.medievalists.net/2020/05/eastern-europe-middle-ages/
Throughout the medieval period, Eastern Europe stood at the crossroads of different traditions—among them Latin, Greek, Slavic, and Islamic—which informed local political, military, economic, cultural, and artistic developments. Whereas the medieval West has established its footing in scholarship and the popular imagination, relatively little is known about the countries, peoples, cultures, and histories of Eastern Europe during the Middle Ages outside of local communities and circles of academic specialists.