The ancients paid great attention to the courtesy of addressing, and it was impolite to address people directly with "surname+first name" (or only when they despised or hated each other). They generally use "surname+word (number)", which is very different from today.
For example, the landlord can understand this very well:
Qin Qiong was a famous general at the end of Sui Dynasty and the beginning of Tang Dynasty. The original meaning of the word "Joan" is a kind of exquisite jade. In the word "Qiong", "Shu" is the ranking, and "Bao" can be understood as "Bao", which can be used as the annotation of the word "Qiong".
At that time, people of the same generation or dynasty called him "Second Brother", "Qin", "Uncle Bao" and "General Qin", which was a respect for him. Only his elders or Yang Lin and other opponents call him by his first name.
In the same way, we can understand the title of Tao Yuanming like this:
Tao Yuanming is famous for diving. The original meaning of "diving" is "submerged and moving underwater", and the original meaning is "deep water, pool". The word "Yuanming" is "crystal clear deep pool", which is just the footnote of the word "diving" (only the water is deep, and the Qing Dynasty can dive freely).
Also, because it has just been said that the ancients generally used the name of "surname+number", the polite title of "Tao Yuanming" has been used ever since. This is why we are used to calling him "Tao Yuanming" instead of "Tao Qian" today.
In fact, just as we often call "Su Shi" Su Dongpo and "Dongpo Jushi" today, we seldom mention his real name, which is also an example of ancient address etiquette.