ELI5: Explain Like I'm 5

Emperor at home, king abroad

The phrase "Emperor at home, king abroad" means that a person's power and status is different, depending on where they are. For example, an emperor is the most powerful person in their own country, but when they leave their country, they may find they are not as respected or powerful. Likewise, a king is respected and powerful within their own country, but may not find the same respect outside of it.