What Is an Emperor's Son Called?

The Emperor could also pursue the election of his heir (usually a son) as King, who would then succeed him after his death. This junior King then bore the title of Roman King (King of the Romans).

What is the emperor's child called?

The term crown prince is not used in European monarchies wherein the hereditary sovereign holds a title below that of king/queen or emperor/empress (such as grand duke or prince), although it is sometimes used as a synonym for heir apparent.

What is the difference between a king and an emperor?

While the title of king is primarily political, the title of emperor often makes one the head of the religion too. While a King rules one fairly homogenous territory (called a nation or kingdom), emperors often wield power over a fairly heterogeneous territory (ruler of many nations).