Why did the man in the iron mask wear the mask?

Answer 1

He was a twin of the king. When they were born the father (not biological btw) has one take away to that the two would not fight for the kingdom. When the lucky twin became king and found out about his twin he had the guy locked up and put in a mask so people wouldn't recognize him.

Answer 2

the masked figure is supposed to be a disease called tuberculosis. when you get it then you dont know you have it unless you start to cough up blood. so someone could have it, and they could give it to you without you even knowing

Answer 3

The man that wears the iron mask is brother of the king of France, Louis XIV. The man that wears the mask is the older brother of the two, therefore the man that wears the mask is the rightful heir. Louis XIV wants to be king so he has his brother secretly locked away in prison so he cannot become king. The mask is so no one can see the resemblance between the Louis XIV and the man that wears it so no one will become suspicious.