There are several synonyms for the phrase "ancient empire." Some of the most commonly used words include "antiquated realm," "old domain," "archaic country," and "historic nation." Other synonyms include "classic civilization," "vintage dynasty," and "early state." These terms are often used to refer to civilizations and empires that existed thousands of years ago, such as the Roman Empire, the Greek Empire, and the Egyptian civilization. Regions like Mesopotamia and Persia are also considered ancient empires, as they were home to some of the earliest civilizations in human history. These synonyms are useful for historians, archeologists, and students of ancient history looking to expand their vocabulary.