Although William Wallace's wife was called Murron in the film, in real life her name was Marian. She was called Murron in the film to avoid confusion with Robin Hood's Maid Marian.
The first time I ever heard the name Murron was when I watched "Braveheart." I loved it - until those first three letters reminded me of the word "murder." Appropriate for that character, yes. For a child of mine? No! =/