Okay kiddo, so back in ancient China, they used to have different kinds of rulers. Some were called sovereigns and others were called emperors.
A sovereign was basically like a king or queen. They ruled over a smaller area and weren't as powerful as an emperor.
An emperor, on the other hand, was like a super king. They ruled over bigger areas and had lots of power.
Now, the "three sovereigns and five emperors" is a list of some of the earliest rulers in Chinese history. It's kind of like a history lesson!
The three sovereigns were named Fu Xi, Shen Nong, and Huang Di. They were said to have ruled China a really long time ago, like thousands of years ago.
The five emperors were named Yao, Shun, Yu, Tang, and Yu again (there were two emperors named Yu!). They also ruled a long time ago and are important figures in Chinese mythology and history.
So there you have it, kiddo. Three sovereigns and five emperors were some of the earliest rulers in China a long time ago, and they were either like a king or a super king.