Do you know anything about buttons

In ancient Rome, the first buttons were used as decorations, and the first pins were used to tie clothes.
In the 13th century, the button served the same purpose as it does today.
At that time, people had learned to open buttonholes in clothes, which greatly increased the practical value of buttons.
In the sixteenth century, buttons became popular.
In The English Middle Ages, shirts were first invented, with the buttons on the left side for women and the right side for men. This was because aristocratic women needed servants to help them dress in the morning, while men wore them by themselves.
In the 16th century, the Chinese introduced buttons to Europe, where they were used only by men, not women, and most people used them as clothing.
Some dignitaries in order to show their wealth, with precious gold and silver, pearls, gemstones, diamonds, rhinoceros horn, antelope horn, ivory precious material, fine button use.King Louis XIV of France is said to have made a royal robe out of 13,000 precious buttons.
Cufflinks is used in special cufflinks shirts, instead of part of the cuff button, it is almost the same size and ordinary buttons, but because of the fine material and shape, the modelling of more styles and personalized needs of customized, good decorative effect, between not careful, let a man originally drab dress and suit the scenery infinite.

Now it's 14#, 16#, 18#, 20#, 60# and so on!
Its substitution formula is: diameter = model *0.635(mm).
If you have a button, but do not know its size, you can use calipers to measure its diameter (mm) and then divide by 0.635.