Imagine being arrested and thrown into jail for wearing a certain colour!
It could have happened back in the days when kings and emperors ruled.
In ancient Rome, only members of the emperor’s family could wear purple or gold clothes.
In China only emperor could wear yellow.
And in France, once upon a time only princess could wear a scarlet dress.
When a person wore clothes in these (royal) colours, it was like wearing a sign saying.
‘’I am the king'' or
‘’I am the emperor'' or
‘’I am the princess''
Wearing a special colour was much easier than wearing a sign.