By virtue of its prevalence and profound clinical effect on the afflicted, it is inevitable that migraine should exert some influence on the course of human history. One especially poignant example involves a man who ranks among the greatest of military leaders, Ulysses S. Grant.

Like his commander-in-chief and spiritual soul mate, Abraham Lincoln, Grant suffered from attacks of clinically severe migraine throughout the years of the American Civil War. In April 1865, at Appomattox Courthouse (Virginia), Grant finally cornered the sparse remnants of Robert E. Lee's Army of Northern Virginia. Grant's fear that Lee once again would elude his grasp, slipping away to join Joe Johnston's force in North Carolina and potentially prolonging the war by a year or more, thankfully had proved groundless. Lee was finished, realized it, and so sent across the lines a note requesting terms of surrender. He did so with some trepidation, as Grant was a commander known variously as "Butcher" for his apparent tolerance of high casualty rates and "Unconditional Surrender" for his harsh treatment of defeated foes.

The previous day, racked by anxiety and impatient to bring his pursuit of Lee to a close, Grant developed a migraine. In his personal memoirs he wrote, "I was suffering very severely with a sick headache ... I spent the night in bathing my feet in hot water and mustard, and putting mustard plasters on my wrists and the back part of my neck" Despite his efforts, the headache persisted into the following morning. He wrote later that he suf*fered still with the "sick headache," but when Lee's note arrived, "the instant I saw the contents of the note, I was cured"

Even so, Grant's mood was muted when later on that Palm Sunday he sat opposite the defeated Lee in Wilmer McLean's parlor drawing up the formal terms of surrender. He wrote that Lee's feelings "... were entirely concealed from my observation; but my own feelings, which had been quite jubilant on the receipt of his letter, were sad and depressed. I felt like anything but rejoicing at the downfall of a foe who had fought so long and valiantly, and had suffered so much for a cause, though that cause was, I believe, one of the worst for which a people ever fought and for which there was the least excuse."

His terms of surrender reflected his subdued mood. Lee's officers would retain their side arms, and all troopers their horses ...so as "to work their little farms." There would be no arrests, imprisonment, or public spectacle.

When the Union batteries began to roar in celebration shortly after the surrender ceremony, Grant sent word to have the guns stopped. "The war is over," he told his staff. "The rebels are our countrymen again" The war indeed was over. The Union was preserved. The "great experiment" (Lincoln's words) in social democracy would not fail, and the South would retain its place in the national community.

Lee's response then and later would mirror Grant's tolerance and compassion. For him there would be no endless guerilla warfare in the hills, no flight to a sympathetic foreign land, no continued defiance. Rejecting more prominent and lucrative positions, he chose to accept the presidency of a small, failing college in the Virginia mountains and spent his remaining years quietly devoted to the education of his countrymen.

How much of Grant's behavior on April 9, 1865 was rooted in migrainous biology? Did his generous terms of surrender result from the dysphoria of a migraine post-drome? Absent acute migraine, how much compassion would he have tendered his defeated foe? In contemplating history, be it that of a country or that of an individual, is it really possible to tease out what is purely "psycho (logic)" from that which is "somatic?"