Mirror-of-princes writing can be explained like this – imagine that you are a king and you want to make sure that your son becomes a good king when he grows up. To do this, you write down a list of rules and advice on how to be a good king. This list is called a "mirror of princes" because it reflects the ideal qualities of a king.
People in the past used to write these "mirrors of princes" for the rulers of their time. They were books filled with stories, wise sayings, and moral lessons. The goal was to show the ruler how to be a good leader and how to rule justly.
These writings were very popular in the Middle Ages, and they were written in many different languages, including Latin, French, and English. Some of these mirrors were written specifically for rulers, while others were written for the general public to read.
Today, we still have mirror-of-princes writing, but it has evolved into a more general concept of self-help books. These books give advice on how to live a good life, how to be successful, and how to be happy. They are like mirrors that reflect the ideal qualities of a person, just like the "mirrors of princes" reflected the ideal qualities of a good king.