Most of the evidence points to the Battle of Bannockburn in 1314 in which Robert defeating the English led by the now inept King Edward II.
Most of Hollywood focuses on William Wallace in the battles he led against the English during this time. Hollywood, however, gets many things wrong. For more info on the history of the battles and of William Wallace, read here.
Many claim that Robert the Bruce was not a great military leader and could not win his own battles without help. They point again to Wallace having to lead the charge against the English to get the Bruce to this point, and that Robert had failed a reported six times and had nearly given up before the seventh time when he won.
One such who supports the claim is Robert Ferguson, author of the book The Knights Templar And Scotland. Ferguson says, "There is now good evidence that a number of Templars, if not most of them, were aware that they were going to be arrested, and they escaped. There's only two places they really could escape to, Portugal and Scotland."
He adds "Given the battle plan that is commonly accepted for Bannockburn, I believe that the Templars were necessary. The existence of Templars at Bannockburn follows a consistent line of facts."
In a book A to Z of the Knights Templar by Gordon Napier, he claims the since the Bruce was excommunicated by Pope Clement V for killing John "the Red" Comyn, he then looked favorably upon the Templars and gave refuge to them when their order was disbanded in 1307, seven years before Bannockburn.
However, these claims are disputed. One such is Helen Nicholson, a professor of history at Cardiff University. She claims "There are no records of any French-speaking knights appearing in Scotland in the early decades of the 14th century in a country where French speakers would certainly be noticed."
She notes that the claim that Templars assisted the Scots against the English goes back to the 19th century. "The myth is being used to show that Robert the Bruce was a weak man who couldn't win his own battles," she said, "rather than the inspirational military leader that he was. I think that the Scots should be fighting this myth. Bruce's battle plan at Bannockburn would have followed best contemporary practice which, as the Templars also did the same, would have meant that there were some elements in common. This does not mean that Bruce had actually met any Templars."
But, when one looks, it is noted that the English were fighting the French at the same times as the Scots, and Wallace did go to France to seek aid, King Philip denied the aid at a time when the French were busy being beaten by the English themselves. But to say that any persons speaking French would have stood out in such a grand fashion would be folly. Also, not all Templars were French...
It is also noted that all of the trials of Templars were not held in Scotland, but rather south of the Firth of Forth, in English controlled territory.
We may not know for sure, as the Knights Templar is a very mysterious group after disbanded and their secrets may never be fully revealed as to what extent they may have helped change the world.