WHEN in 1513 a large Scottish army, led by a brilliant king, faced down a smaller, sicklier and exhausted English force under the leadership of an elderly soldier, it looked as simple a case of national conflict as you could imagine, and with a predictable result. Scratch the surface, however, and you discover that definitions of Scottish and English, and concepts of loyalty, were far more complicated, and dangerous.

One more in a line of Scottish kings who could not thole what they perceived as their southern neighbour’s domineering behaviour, James IV of Scotland had picked a fight with Henry VIII. Embroiled in conflict in France, Henry sent his B-team north, led by the supremely gifted strategist, Thomas Howard, Earl of Surrey. What followed, as every schoolchild in Scotland ought to know – though too few do – and almost nobody in England apart from a handful of Northumbrians ever remembers, was the Battle of Flodden, one of the most devastating military defeats we have ever suffered.

In the space of a couple of hours, on the rolling lush pasture around the village of Branxton, a few miles south of the border, more than 10,000 Scots are thought to have died, and around 3,000 English. Even worse, the ruling class was all but extinguished, taking the king, his son, and too many of those in charge of parliament, church, and trade.

The circumstances that led to this entirely unnecessary confrontation, and its dreadful outcome, were the subject of my first novel, After Flodden. In its sequel, Dacre’s War, I pick up the story 10 years later, when Scotland is a shadow of its former self. Ruled by an often absent Regent, the Duke of Albany, who is more French than Scottish, the country is in the grip of sorrow, fear and paranoia. The north of England is the bailiwick of the cunning robber baron, Lord Thomas Dacre, who is warden general of the English border, or marches, and is more powerful in these parts than the king himself.

Slowly, however, he comes to realise that he has an enemy in the borderlands who will not rest until he has brought him to justice for a murder committed on his command, many years before. That enemy is Adam Crozier, leader of a small clan from near Jedburgh, one of dozens of such families and alliances that dominated these parts.

One of the fascinations of the early 16th century is that so many of its most important political events – from a Scottish perspective, at least – are played out across the borders. The Highlands had its noble and aristocratic clans, but those in the borders were much less blue-blooded and grand. They were far more likely to be led by commoners, such as Crozier, or by criminals and outlaws, or at the very least by those prepared to defy the law whenever required.

For the likes of Dacre and Crozier, national allegiance was of secondary or even no importance to them and their followers. Self-preservation was their main concern, and they would make alliances with those on the other side, legitimate or criminal, if it would help them hold onto power, or bring down their foes. Parallels with the ever-shifting connections and associations in the Middle East today are all too obvious.

No doubt Baron Dacre, being part of the king’s court, considered himself a proud Englishman. But in Crozier’s case, as with many who fought – or refused to fight – at Flodden, his identity was undoubtedly that of a Borderer, rather than a Scot. When you read of the way in which even a humane and far-sighted king like James IV treated those he considered border scum, joining forces occasionally with the English king and his henchmen to rid the dales of rustlers, thieves and killers; and when you think of the way in which armies from both sides ravaged the land that lay between them and the enemy as they passed, it is little wonder that Borderers had scant sense of loyalty to the nation’s cause.

And yet, although they would never have used the word, the concept of independence was central to everything these clan members did. Unlike Dacre, they were under no monarch’s or regent’s or lord’s command except when it suited them. Staying out of the official eye, avoiding the courts and the gibbet, and answering only to their chieftain was a borderer’s definition of freedom.

The palaces of Holyrood and Linlithgow, where state affairs were conducted, must have seemed almost as distant as a space shuttle is to us today. Judging from contemporary records, the people of this area held the authorities in contempt. The harsh and violent world along the invisible line that divided the countries, carried on its business regardless of the crown. The fierce, untamed, treacherous inhabitants would have scoffed at the idea of nationalist sentiment. Some, I’m told, still do.

Dacre’s War, by Rosemary Goring (Polygon, £8.99)