This was another one of those movies that I was forced to attend because my girlfriend at the time had a thing for Leo (I believe this was a rather wide-spread phenomenon.) However, it is another one of those films that I believe there were tons of better options available out there rather than Leonardo DiCaprio.
This film is very loosely based on a novels by Alexandre Dumas in that the Three Musketeers are in it. Mostly it focuses on King Louis who is played by Leo. The Kingdom of France isn't doing so well and the people are suffering because of the expenses on war and the own lavish lifestyle of King Louis who continues to rule with an "iron fist" despite the fact that the country is bankrupt.
The Man in the Iron mask is a guy locked away in a prison who has a (you guessed it) iron mask on. It has been fixed in place because the man is actually Louis' twin brother Phillipe, who obviously is also played by DiCaprio. While the idea of having a mask locked in place for years is gruesome enough to hold my attention, the rest of the story is actually pretty boring and it really drags on.
The Musketeers break out Philippe and attempt to insert him onto the throne only to have some stuff go wrong and then eventually win in the end. There is no real plot here. I think most people could have predicted this would happen simply by watching the trailer.
United Artists were very aware of what they were doing here. They took advantage of Leo's post -Titanic fame and made what they almost certainly knew was a mediocre film. It is riddled with historical inaccuracies and even blunders such as having portraits of famous French people who weren't yet born during when this film was meant to take place. I can forgive all of this, but Leo's performance was not good in this and really, neither were any of the other costars. I found just about everyone's performance to be dreadful and once again Leo is not a believable adult.
You don't need to watch this movie unless you are having trouble falling asleep.