Some people say that Li is Yuan Tiangang's apprentice, while others say that they are brothers. What is their relationship?

The official history doesn't seem to introduce the exact relationship between Li and Yuan Tiangang. Many of their relationships are rumors. One saying is that they are bosom friends, and the other is that they are brothers.

Li and Yuan Tiangang were famous intellectuals in the Tang Dynasty. Many mysterious and magical stories happened between them. They have their own opinions on astronomical phenomena and technology. They also cooperated to complete a famous work called TuiBei. The exact relationship between them is not given in history, but there are many rumors.

Some people say that they are just classmates and friends who study together. They discuss academic research with each other and study astronomical phenomena, principles and changes together. They had a long talk and discussed with each other, and they were all famous people in history. It is said that when they wrote "Push Endorsement" together, they were good at different aspects. One person is in charge of writing and the other is in charge of drawing. They still have a clear division of labor.

There is also a saying that they are half-brothers, or they may be brothers of multiple births. As for why two people, one surnamed Li and the other surnamed Yuan, were raised by people surnamed Li and Yuan respectively after their birth. As for why they all have these strange talents, it is because Yuan Tiangang's mother gave him a book when he left, and Yuan Tiangang and Li are both brothers, so they all study this gobbledygook together, so they all have these strange talents and they all have the ability to predict the future.

These statements are all rumors and are not clearly recorded in the official history.