CAMBRIDGE, England — With his arrest on Monday after more than 12 years on the run, Radovan Karadzic seems virtually certain to face trial in The Hague — and, at 63, the prospect of life imprisonment — for his role in masterminding massacres that war crimes prosecutors have described, in indictments drawn up against him, as “scenes from hell, written on the darkest pages of history.”

But in his own mind, at least until he vanished from view in 1996 and became one of the most hunted men in Europe’s history, Mr. Karadzic saw himself as a sophisticated intellectual, a psychiatrist and poet with an intuitive understanding of his people, the Bosnian Serbs, and of the challenge to their survival, as he saw it, that came with the breakup of the former Yugoslavia in the early 1990s.

It was in his intellectual guise that he liked to present himself to visitors at the height of his power, when he ruled as president of the self-styled Srpska Republic and supreme commander of its armed forces, in the mountain redoubt of Pale, above the besieged city of Sarajevo.

At the Panorama, the converted ski hotel he used as his headquarters, he liked to hold court, of an evening, and make a show of his grasp of culture, politics and history.

It was a Lilliputian scene, at once absurd and menacing. Only a few miles away, artillery guns under his command were shelling Sarajevo into rubble, filling its soccer fields with graves, with a toll of more than 10,000 killed before the siege ended. Further afield, murderous paramilitaries working in the Serbian nationalist cause were driving tens of thousands of Muslims and Croats from their homes, making refugees of 1.5 million people, in the process known as “ethnic cleansing.”

Still ahead, in those first two years of the war that lasted from 1992 to 1995, was the worst atrocity of all, the one that came to define the madness that seized Mr. Karadzic and his partner in the Bosnian slaughter, the army commander Gen. Ratko Mladic, who remains uncaptured even as the government in Belgrade prepares to hand Mr. Karadzic over to the tribunal in The Hague: the genocidal massacre in 1995 of nearly 8,000 Muslim men and boys in Srebrenica.

One night in the late spring of 1992, brandishing a Cuban cigar and downing successive glasses of French cognac, Mr. Karadzic admonished a reporter from The New York Times for a dispatch from eastern Bosnia in which the reporter described terrified groups of Muslim women and children fleeing across the mountains from towns overrun by Serbian paramilitaries, who had gone house to house rounding up Muslim men, and killing them. This, the reporter had written, was the reality of “ethnic cleansing.”

“No, no, no,” Mr. Karadzic said, leaning forward intently at his desk. As though correcting an errant pupil, he said the reporter had failed to understand ethnic cleansing, presenting it as an abomination to those taking to the mountains, whereas it was, in reality, quite the reverse. Far from being forced from their homes, he said, the fleeing Muslims were being given an opportunity for which they should be grateful — the chance to “return” to the only place they could ever truly be at home, in towns and villages elsewhere where they could live with other Muslims, away from Serbs.

As a rationale for genocide it was dizzying, but at the same time wholly in character for the preposterous streak in Mr. Karadzic, who seemed to have been forged by the vicissitudes of his past to become the principal architect of an attempt to re-engineer Bosnia's conflicted history.

Born to a poor rural family in Montenegro on June 19, 1945, he carried in his bones much of the tortured history of the region during World War II, when his father, Vuk, was a member of the Chetniks, Serbian nationalist guerrillas who fought the Nazi occupiers of Yugoslavia and the communist partisans of Tito.

When the Chetniks lost to Tito, his father went to jail, and he had a lonely childhood in the care of his mother, Jovanka, learning from her the romantic legends that have sustained Serbian nationalism for centuries.

In 1960, he moved to Sarajevo, and graduated from the university there in medicine, specializing in psychiatry. He concentrated on paranoia, but developed a reputation among colleagues at the university, where he taught, and among patients, for a quirkiness of character and professional lapses that made him, among the city’s intelligentsia, something of a figure of fun.

At the same time, he wrote and published his own poetry, hiring halls at the university for public readings of work that critics in Sarajevo tended to belittle for its dark and often obscurantist themes, many of them rooted in Serbian legend.

In his personal style he was florid, given to double-breasted suits and a carefully coiffed shock of hair. Later, as a war leader, he liked to don camouflage fatigues, and have his photograph taken with the gun crews shelling Sarajevo. He was a celebrated gourmand, becoming heavily overweight by the time that he made his mark in politics.

He began as a liberal, but as the strains on Yugoslavia’s survival grew after Tito’s death in 1980, he moved to the right, helping to found, in 1990, the Serbian Democratic Party that became the vehicle for hardline Serbian nationalism in Bosnia, and a handmaiden in the cause of a Greater Serbia that found its principal champion in Slobodan Milosevic, the Serbian leader in Belgrade.

In April 1992, after the Muslim leader in Bosnia, Alija Izetbegovic, declared the republic’s independence, Mr. Karadzic, declaiming against what he described as a plan to implant an “Islamic republic” in Bosnia, left Sarajevo for his Pale redoubt and declared the foundation of the separate Serbian republic.

The grandiose manner he developed in the years of conflict was encouraged, many who knew him then believed, by the willingness of the United Nations and the Western powers, primarily the United States and Britain, to negotiate with him, in Pale and at diplomatic encounters across Europe.

Talks with emissaries like Cyrus R. Vance, the former United States secretary of state, and David Owen, the British foreign secretary at the time, took place even as the paramilitaries enlisted in the Serbian cause were laying waste to much of Bosnia. The death toll from the 43 months of war has been estimated at between 150,000 and 200,000, and United Nations investigators have concluded that the deaths were accompanied by as many as 20,000 rapes.

Fearing arrest under United Nations war crimes warrants following the 1995 Dayton agreement that ended the war, Mr. Karadzic and General Mladic quit their posts and went into hiding.

Despite numerous raids by NATO troops, many led by American units, both men remained at large until the announcement on Monday.

Successive chief prosecutors at the Hague tribunal belabored NATO commanders in Bosnia, and their political superiors, for being, as they implied, insufficiently zealous in their pursuit of the two fugitives.

In Montenegro and in Serbian nationalist strongholds in Bosnia, Mr. Karadzic continued to be feted, in absentia, as a hero, with his image printed on T-shirts and his name painted on walls. In 2004, he even managed to get a novel published in Belgrade, and newspapers there said he had been spotted relaxing at cafes in the Serbian capital.

In an Op-Ed article in The New York Times in 2003, Carla Del Ponte, then the chief prosecutor at The Hague, expressed her own outrage.

“Only when fugitives like Dr. Karadzic and Gen. Mladic are transformed from symbols of a lack of backbone into symbols of the international community’s resolve will Bosnia and Herzegovina and the other traumatized states of the region stand a chance of establishing rule of law,” she wrote. “The time has come to summon the will and bring Radovan Karadzic and Ratko Mladic to justice.

“It’s what their victims, and the rest of the world, deserve.”

Copyright 2008 The New York Times Company