More than 200 years ago, there was a Prussian kingdom in today's German land, and a king named Frederick II came out of the Prussian kingdom. He was ambitious. Soon after he came to power, he invaded Silesia, conquered Fries and carved up Poland. ...

Frederick II's great achievements depend on his well-trained army. He attaches great importance to the peacetime training of the army, which is famous for its strict military capacity and discipline in Europe. To this end, the king often relishes that he is a military "genius".

One day, after a great victory, Frederick II ordered a grand military parade.

In the golden sunshine, Prussian soldiers wore woolen uniforms and polished shoes. They are neatly arranged, all standing straight and full of energy. Accept the inspection by His Majesty the Emperor.

Accompanied by ministers, Frederick II walked through rows of teams. The cheers of the soldiers "Long live the emperor" satisfied him, and he nodded and waved happily.

Suddenly, he stopped in front of a soldier and asked him to stretch out his sleeve. He found that the soldiers' sleeves were dirty and shiny, which was simply the light of learning from the scriptures. He checked a few more soldiers and found that the situation was similar. So he angrily reprimanded them and asked the soldiers why they were so careless about hygiene, which affected their military strength.

An officer hurried forward to report: "Your Majesty, the soldiers are very hard. If they want to March and fight, they must sweat. Sweat on your forehead will block your view. At this time, it is often too late to take a handkerchief, so we have to wipe the sweat with our sleeves. Therefore, please forgive them. "

After listening to the report, Frederick II felt very reasonable and held back his anger. Back in the palace, he mused that it was reasonable for soldiers to wipe sweat with sleeves, so he held back his anger. Back in the palace, he mused that it is understandable for soldiers to wipe their sweat with sleeves, but the Prussian army is the bravest and most skilled army in the world, and it should also be the most civilized and hygienic army. We must find a way to prevent soldiers from wiping sweat with their sleeves.

After some research, he came up with a good way to prevent soldiers from wiping sweat with sleeves: sew some metal buttons on the sleeves of military uniforms, so that if you wipe sweat with sleeves again, you will cut your face, at least it will be very uncomfortable.

At the emperor's command, the sleeves of Prussian soldiers' uniforms were quickly nailed with metal buttons, and the cuffs were no longer dirty. This method was quickly popularized in the military uniforms of European countries.

Later, people saw that the cuffs of soldiers had buttons, which looked beautiful and generous, and they followed suit. So the cuff of the suit began to nail a row of buttons.