Continuing his 40-part history of Scotland, Michael Fry recounts a complex story of disputed inheritance which became a focus for popular disaffection and a mirror of the nation's state

AT twilight on Thursday, March 2, 1769, a lone, weary horseman rode up the High Street of Edinburgh, gathering a train of the curious behind him. He was Ilay Campbell, a middle-aged advocate who had spent three days in the saddle coming from London, as the onlookers knew.

They probed him with excited questions, but he kept silent. He was quite typical of his profession, a small, impassive man of a dry, somewhat ineffective manner. In court he vexed listeners with his low, dull voice. But on reaching the Cross and turning round to face those following him, he raised it. ''Douglas for ever!'' he cried.

The crowd went wild. And their excitement sped through the city. That night its people set out to get drunk, as a prelude to three days of revels. They were celebrating what they saw as victory in the great Douglas Cause, at any rate the successful appeal to the House of Lords after seven years of legal wrangling by their chosen hero, 21-year-old Archibald Douglas.

In those days occasions of public rejoicing, a battle won or a royal birth, were marked by so-called illuminations, when householders put lighted candles in their windows. The tipsy crowds on the streets of the capital reckoned the Douglas Cause was in the same league. They took it amiss when they found some houses still dark, so much amiss that they thought the curmudgeons behind the curtains ought to be punished.

The first to suffer was the Lord President of the Court of Session, Robert Dundas, Lord Arniston. The mob shouted insults and stoned his windows. Another judge to suffer the same indignity was Alexander Boswell, Lord Auchinleck. here, at the front of the yelling, gesticulating crowd capered his son, James, an advocate with literary pretensions.

This rabbling of the justiciary continued through a bleary morning after. In Parliament House, Lord Hailes was quietly hearing a case when somebody shouted: ''They are attempting to pull the President out of his chair. '' Everybody rushed for the doors. The judge followed, fearing Arniston was under assault on his own bench. He found Lord Pitfour and gabbled: ''They are pulling the President out of his chair. We must go and share fates with him!''

Both hurried to Arniston's courtroom: ''There, there was nothing but bare walls. This confirmed me in the opinion that Civil Justice was annihilated. I called for a macer that I too might go out in form. '' Only then did he discover that the Lord President had not yet arrived: the chair was the sedan chair the portly judge always hired to be carried to work, which had been threatened in the street.

Seldom did Scots vent wrath on their legal system. It was, after all, a symbol of their nationhood, guaranteed in the Treaty of Union. Now that serious politics had vanished to Westminster, lawyers came to play a major role in every aspect of public life, not only in law and order but in the many efforts at social, economic, and cultural improvement by a country desperate not to be provincialised.

These efforts often entailed a casting off, tinged as it might be with regret, of old ways, the things that made Scotland Scotland yet. They meant, too, that the law had to be adapted to new purposes. That was why some of the era's most dramatic episodes, catching the popular imagination, were legal ones, and why the courts became a theatre of human, even national, destiny.

Such was the Douglas Cause. In James Boswell's words, it ''shook the sacred security of birthright to its foundations''. Scotland was an insecure nation, obsessed with status and safeguards for it. The cause struck through the inarticulacy of her political life to the heart of that obsession.

It had all started as an affair of the heart, with Lady Jane Douglas. Few women have been so endowed with beauty and fortune for a life of sorrows. She was born in 1698, sister of Archibald, first and only Duke of Douglas, whose patrimony was as ancient as it was vast. Wild and vindictive, he never married. It thus fell to her to continue the line.

This ought not to have proved difficult. Her youth's bloom was exquisite, her simple charm touched all. At 22 she was betrothed to Francis, Earl of Dalkeith, heir to Buccleuch. It would have been a brilliant match, but the engagement was broken because of Douglas's insane jealousy.

Lady Jane stayed in seclusion with her mother at Merchiston Castle, her loveliness paling, if not fading. Nothing disturbed this long, drear spinsterhood but the mother's death, whereupon Lady Jane set up her own establishment at Drumsheugh, just to the west of Edinburgh.

Into her life then swept for a second time (his suit had once before been rebuffed) Colonel Sir John Stewart, a tall, suave wastrel, a Jacobite who had been out in 1715. He fled to Sweden, whence he returned after years of soldiering, penniless as ever. He hung around Edinburgh in the autumn of 1745, seeing what he could pick up.

Lonely Lady Jane fell for him. He took her to Holyrood to meet Prince Charles. With the Whigs back once the Highland army marched on, he got her at some risk to hide Jacobite stragglers about Drumsheugh. In August 1746 they married in secret, and left for Holland. It was no time for men like him to tarry, while she still had her brother to fear.

They were heard of only through the odd letter home. In the spring of 1748, Lady Jane wrote one to the duke confessing she was wed. And that July, in Paris, she bore twin sons, Archibald and Sholto. In November they all went to London, where Stewart was imprisoned for debt. Lady Jane came back to Scotland, anxious to have her sons acknowledged heirs of Douglas, so as to bring to an end their careworn existence of destitute wandering.

But her brother had hardened his heart. He refused to see her, even though she lingered for three days with the boys before the gates of Douglas Castle. She was prostrated by grief when Sholto died in April 1753. She followed a few months later after a painful final illness, affirming to the end that Archibald was the true heir whether acknowledged or not.

The duke, however, went out of his way to show that their estrangement stretched beyond the grave. Drawing up his will, he named as heir a cousin, the Duke of Hamilton, who in the event was to predecease his benefactor and leave his claim to an infant. Seven years passed, till Douglas himself lay dying. Now, for reasons we cannot fathom, he relented, bequeathing all to his sister's son. Archibald Stewart (from then on calling himself Douglas) was served heir to his uncle's estates.

The Hamiltons were not unnaturally aggrieved. In fact they would move heaven and earth to get the disposition overturned. Their man of business, Andrew Stuart, was an elegant, brilliant lawyer in Edinburgh, not yet 40, but solemn and cautious enough. Strangely, he had also worked for Douglas before the duke's abrupt change of mind. In the course of his duties he convinced himself that Lady Jane, from whatever tragic reasons, was guilty of an imposture.

In a preliminary probe, he tried to prevent Archibald's succession on a technicality of the land laws. It failed. At the end of 1762, he raised a new action calling on the Court of Session to declare that the young man was not the heir of Douglas, nor indeed Lady Jane's son at all.

The evidence, though circumstantial, proved difficult to ignore. It was strange that lady Jane should have been a 50-year-old primigravida in the first place, though not, of course, out of the question. Stranger still was that there seemed to be no witness to the births, except an evasive servant. Four letters supposed to have been written by the French surgeon in attendance were patently botched up later by someone whose native language was English, probably by Colonel Stewart.

He himself protested that the confinement had come to an end so fast that he had not had time even to finish dining and arrive at the bedside before his wife was delivered. He was disastrous under cross-examination, randomly throwing out contradictory statements, smiling foolishly, shrugging fecklessly if pressed on them. It came as no surprise when in July 1763 the court decided there was a case to answer: though Stewart, who died the next year, did not in the event have to answer it himself. The battle could begin in earnest.

Andrew Stuart extended his inquiries through agents in France, and raised a second action in Paris. It accused the Stewarts of ''supposition of children'', a practice common enough to have been declared a crime, indeed a capital one, under French law. In fact this was a formal device to flush out more evidence. It uncovered the coincidence that, at the relevant date, the new-born son of a poor glazier had been sold to a blue-blooded foreign couple.

But Stuart's zeal got him into trouble at home. The terms of the French edict he secured, assuming commission of a crime, offended a Court of Session jealous of its prerogatives. He was ordered to wind up his action in Paris. This proved time-consuming and cost the Hamiltons much sympathy meanwhile. Given the convoluted procedures of Scots law, it was June 1766 before they were ready to present a case in Edinburgh.

In Scotland the matter had become political, and produced marked divisions, with a significant pattern to them. On the whole, the great minds of the Enlightenment supported the Hamiltons. Adam Smith, already with an international reputation as author of The Theory of Moral Sentiments and now working on The Wealth of Nations, had acted as one of Stuart's agents in France, where he happened to be a tutor to the young Duke of Buccleuch on a grand tour. David Hume, even more renowned for his Treatise of Human Nature and beginning a huge History of England, said Hamilton's side carried the ''force of Reason'', while Douglas's represented ''the most violent torrent of prejudice that ever was heard in a private cause''.

Other men of letters rallied round because of their debt to David Mure of Caldwell, one of Hamilton's legal guardians, who had also been a confidant of the Earl of Bute, the first Scottish Prime Minister since the Union, hounded from office for that very reason a few years before. Till he went, though, he had through Mure handed out many favours to hungry Scots philosophers, who now returned them. Another tinge to this motley crew was added by Hamilton's leading counsel, one of the last Jacobites, Alexander Lockhart, Dean of the Faculty of Advocates and son of the Old Pretender's principal agent in Scotland.

What bound them all together was a link of some kind to Mac Cailein Mor, the greatest chieftain in the Highlands, head of mighty Clan Campbell, the Duke of Argyll. The current duke was the fourth to hold that title, a bluff but kindly soldier, of all the king's commanders the most merciful to the defeated rebels after the '45 (thus, for the suspicious, tainted with Jacobitism). Since 1761 he had filled with no great relish the shoes of the cousins he succeeded as virtual viceroys of Scotland. Argyll's interest in the Douglas Cause came through his wife-to-be, the widowed Duchess of Hamilton, mother of the boy who had inherited the suit against Archie Douglas. If he won, the Campbells would have 10 years of making hay with his inheritance. This was too much for the Scot in the street, who had had enough of their great aristocratic house's haughty manipulation of his government and religion.

So the Douglas Cause was also a people's cause, perhaps in an embryonic form even a radical cause. That the people should support Archie Douglas, Scotland's largest landowner-in-waiting, was perhaps odd. But they were moved by Lady Jane's suffering, appalled at a callous determination to rob her son, and angered by the greed of the Campbells and Hamiltons. We have seen in our own day how submerged social and political forces can find an outlet in the idealisation of a wronged, noble figure.

That was why Douglas could engage as his counsel some of the best of a new generation at the Bar, men who owed little to the high aristocracy, nor yet to social affection, but relied on their own abilities. They tended to come from backgrounds the Enlightenment had hardly touched, from old-fashioned, plain-spoken, hard-drinking, God-fearing families, who used Scots in public and private and felt proud of their forefathers' presbyterian nationalism.

One was James Montgomery, Lord Advocate, who had snapped up a forfeited Jacobite estate and spent much time on other speculations, not very successful, in land. A second was Henry Dundas, brother of the Lord President, setting out on a career which would reach political heights of which the Argylls never dreamed. A third was James Burnet, soon to go on the Bench as Lord Monboddo, an eccentric derided for his theory that men were related to apes. A fourth was Robert Macqueen, whose dark brows, glowering looks, thick accent, and growling voice would terrify everyone when, as Lord Braxfield, he condemned mincing reformers.

In the Court of Session, the pleadings lasted 21 days, the longest ever known there. At the end of it all, the judges, whose heads must have been reeling from the weight and complexity of the evidence, ordered it to be summarised for them in memorials. This was normal in very difficult cases. But it meant the proceedings, already four years old, would be dragged out still further. The court eventually had before it 173 documents printed in four volumes of 4000 pages each.

It was thus July 1767 before the Douglas Cause came to a judgment. Half Edinburgh seemed to throng Parliament House. All eyes were on Archie Douglas, who certainly looked like a common Frenchman, with a swarthy complexion and low brow, though he was much refined by his education at Rugby and Winchester. But many eyes doubtless wandered to the dowager Duchess of Hamilton, a strikingly handsome woman, representing her son, a delicate lad who stayed away for fear of the crush; in a couple of years he, too, would be dead.

The procedure was for the judges to give their votes in order of seniority. If there was a majority among the 14 lords ordinary, that would determine the cause. If not, the Lord President had a casting vote. A betting man (and wagers of #100,000 were placed on the outcome) would surely have put his money on Arniston's declaring for Douglas. All his previous personal and political connections spoke for it, and he had his brother pleading on that side.

But he was never a man to gratify expectations. He led off in his blunt way: ''The simple fact before us resolves into this question - is the defendant the son of Lady Jane Douglas or not? And I am sorry to say it, that my opinion in this great cause, after the utmost pains and attentions I could bestow, is clearly against the defendant.''

He spoke on a Tuesday, the delivery of the other verdicts taking the whole of the rest of the week. By Friday, the votes stood at six for Douglas and six for Hamilton. When the court resumed on the following Tuesday, another was added to each side. Arniston thus had the casting vote, and few could doubt what he would do with it. He said tersely: ''As this is a cause of civil property, I think myself bound to give judgment according to my own opinion. ''

In the Court of Session, therefore, Hamilton had won. But on so fine a balance an appeal was inevitable to the House of Lords. The cause could not be heard there till January 1769. The decisive voice was that of the Lord Chief Justice, William Murray, Lord Mansfield, a Scot educated in England, where his ruined Jacobite family had sent him to stop him being infected by their allegiance.

A betting man would surely have wagered on Mansfield's support of the Hamiltons - again, all his previous connections spoke for it. But again a betting man would have been wrong. After a magnificent oration by the Lord Chief Justice in favour of Archie Douglas, his fellow judges reversed the Court of Session's verdict on February 27. Ilay Campbell, one of the delegation of advocates who had gone to Westminster, rode straight to Edinburgh.

It was a very Scottish affair, the Douglas Cause, in the swings it took from one extreme to the next, provoking ecstasy in some, agony in others, and turning on the nicest points argued out with all the more ferocity for that.

It exposed the political condition of Scotland too, in an era when Scots did better to keep their opinions to themselves. When this time they could not bottle up their feelings, they revealed contrary aspects even of the prevailing Whig ideology (leaving Jacobitism quite out of account).

On one side was Argyll's dominant faction, very unionist, at best benevolently despotic, at worst authoritarian, believing in the state rather than the Church, enlightened, improving. On the other side stood lesser men, setting store by personal independence, readier to stick up for Scotland, believing in the Church rather than the state, anti-intellectual, suspicious, conservative. Both sides had deep roots in the nation's past. Both would shape its future.

n The next instalment of Michael Fry's Millennium Project will appear on Thursday, March 5.