England's Edward I had styled himself the Hammer of the Scots with good reason. The intervening decades had brought Scottish morale to an all time low. There was as much a psychological war to fight, as any on the battlefield.
Many ordinary Scots just wanted to give up. Accepting their vassal status in return for peace.
Edward I was now dead. But his son Edward II could call upon the same nobles and their armies; aged veterans of his father's campaigns, riding alongside sons eager to match their sires in valor and glory.
Robert the Bruce could not command the numbers, nor rely upon the resources, of his battle-hardened overlords in the south. The English would outnumber the Scots, at least three to one (maybe more), on the Battlefield of Bannockburn.
Then too was a personal level, whose pressures cannot be understated. Imagine a man, any man, whose wife, daughter and sisters had all been held hostage by the enemy for seven long years. Their lives and continuing good treatment rely upon his submission. Their execution and torture could easily result from his lack of compliance; a punishment for his rebellion.
Nor were these idle threats. Three of Robert's brothers had been captured by the English, during earlier bids for Scottish independence. Neil, Thomas and Alexander Bruce had all been hanged, drawn and quartered. It was only a veneer of chivalry which had saved the women.
As a husband, father and brother, Robert's instincts must have been to race into England and rescue them all. He had to have day-dreamed of such heroics. But as a statesman, he had a responsibility for his country's freedom. Even if much of the population sneered or feared such attempts.
The example of his brothers taught him quite eloquently his own Fate, if he should be captured too.
Robert Bruce was a human being, and that was what made him a hero.