In the eyes of Qianlong and his ministers, the west is a barbarian country. They don't pay attention to food and clothing and personal hygiene like wild animals, so they look down on them very much. They only think that the Qing Dynasty is the strongest and most powerful. But in fact, during the stagnant period of the Qing Dynasty, western countries have made great progress and made many advanced inventions. At that time, the British king sent envoys with a large number of guns and ammunition to meet with Qianlong, hoping to increase friendly relations between the two countries, but Qianlong rejected them.
He hastily dealt with a few words of the British envoy, then threw all these guns and ammunition into the warehouse and continued to daydream smugly. A few years later, the British envoy came to worship again, and Qianlong remembered those guns at that time. When he opened the warehouse, he found that they were all rusted and could not be used, which made Ganlong think that these things were inferior and China's swords were better. But in order to show the tolerance of a country's son of heaven, Qianlong wrote a letter to the king of England.
The main idea of the letter is that we lack everything in the Qing territory and don't like your opportunistic things. If you like Chinese porcelain and jewelry, you can buy some every year. Between the lines, we can see how much Emperor Qianlong despised Britain. More than ten years later, foreign invaders entered the Qing Dynasty with advanced weapons and hit Qianlong in the face. If he had been more modest and communicated more, the Qing Dynasty would not have declined so quickly.