When it comes to periodization what is a good example of a turning point?

A notable turning point in periodization is the transition from the Classical to the Medieval period, marked by the fall of the Western Roman Empire around 476 AD. This shift not only changed political structures but also influenced culture, religion, and societal organization in Europe. The rise of feudalism, the spread of Christianity, and the establishment of new kingdoms exemplify the profound transformations that characterize this new era. Such turning points highlight the dynamic nature of historical periods and their interconnectedness.