Braveheart is a ridiculously factually incorrect movie. Mel Gibson abused artistic licence.
"Prima Nocta" ie. "First Night", the law where English lords could bed the wife of a Scotsman on the night of her wedding was not brought in by Edward, this was made up.
Braveheart was actually a title given to Robert the Bruce after his prowess in the wars of independence, not William Wallace.
Wallace would never, ever have met the queen, Edward II's wife. When Wallace was fighting these battles, she was an infant, so he most certainly did not get her pregnant.
That's to name but a few.
My personal favourite:
When asked by a local of Stirling why Mel Gibson took out the bridge in the scene of the famous battle of Stirling Bridge, he replied that it "got in the way". The local promptly replied "Aye, that's what the English found too".
I could rant about this one all day. The fact that there was a bridge in this battle was what made it possible to win. Wallace's forces were outnumbered by about 10,000 men, their forces largely built with poorly trained and equipped commoners, while the English army consisted of plenty heavy cavalry and trained foot soldiers. He was also joined by Andrew Moray in commanding his army.
They would not have won were it not for the narrow bridge crossing the Forth that the English were forced to cross before they could reach the Scottish forces. Wallace waited until just enough of the English forces that he felt the Scots could handle had crossed, then sounded the charge. The English were slaughtered - those on the Scots side could not retreat since the bridge was too narrow (two horses breadth) and the forces on the other side could do nothing to get over to help. The English forces were either killed, drowned trying to get away or fled as they helplessly watched their comrades get slaughtered.
Please excuse the massive rant, I just hate that movie so much. =.=