Final answer:
The term 'Eastern Region' can refer to different areas depending on historical and geographic context. In Europe, it might relate to Eastern Europe, while in Asia, terms like 'China Proper' or 'Russia's Eastern Frontier' would be more appropriate depending on the location being referred to.
Step-by-step explanation:
What is now known as the Eastern Region was once referred to by different names depending on historical and geographic context. For example, Europe is traditionally divided into Western Europe and Eastern Europe, with Eastern Europe being east of Germany, Austria, and Italy. However, the terms such as the Ancient Near East or Middle East were used by Europeans when referring to regions east of the Mediterranean Sea, often in relation to their position in the 'West'. In the context of the question, if we are referring to Asia, specifically regions related to China, 'China Proper' might fit the description of an Eastern Region that was known by another name.
If, on the other hand, we are referring to historical aspects of Russia, the Eastern Region beyond the Urals was and can be referred to as Russia's Eastern Frontier. It's important to understand that the designation of regions as eastern or western has often been a matter of the perspective of the person or culture making the description. Given the various options and without a more specific geographic focus, it's challenging to provide a singular previous name for the 'Eastern Region.'