The Man in the Iron Mask (1939)

Tyrannical King Louis XIV learns that he has an identical twin brother Philippe who was raised from birth by his late fathers trusted friend DArtagnan and his faithful musketeers Porthos Athos and Aramis After Philippe falls for the kings betrothed Spanish Princess Maria Theresa Louis imprisons him forcing his brother to don an iron mask that will slowly suffocate him and its up to DArtagnan to rescue him