Their friendship was brief, lasting five months. But its intensity was forged in the cauldron of World War I — a clash the United States entered 100 years ago this week.

Richard Newhall, a 28-year-old Harvard history scholar and second lieutenant from Minneapolis, was one of more than 118,000 Minnesotans who served in the First World War. He jumped from a muddy trench on May 28, 1918, joining 3,500 soldiers attacking German front lines near the French village of Cantigny.

Before leading his platoon into battle, Newhall elbowed through the crowded trench to find his best friend and fellow lieutenant, George Haydock. They spoke of trivial things, pinpointing landmarks by which to direct their movements.

"Neither of us seemed to have any feelings of parting, any realization of imminent danger," Newhall later wrote.

Blowing his whistle, Newhall climbed into the bright dawn sunshine about 6:30 a.m.

"As he stepped forward amid the smoke, amid the din, amid the chunks of earth peppering the sky from the rolling barrage, Newhall chanced a look to his right," according to Eden Prairie author James Carl Nelson's riveting account in his book, "Five Lieutenants."

Newhall caught a glimpse of Haydock leading his platoon. It was the last time he saw his friend. As we mark the 100th anniversary of the U.S. entry into the Great War, "Newhall's experiences 'Over There' shine a spotlight on that war and the lives it shattered," Nelson said in an interview. "Newhall and Haydock's relationship is an undeniable love story, for sure."

Born June 12, 1888, Newhall was the fifth of six kids of a Minneapolis real estate broker. He grew up at 2702 Humboldt Av. S. near Lake of the Isles. Entering the University of Minnesota in 1906, Newhall became smitten with history and spent the summer of his freshman year drilling at an ROTC camp at Fort Snelling.

Nelson, an award-winning author, graduated from the U in 1983 — 72 years after Newhall picked up a master's degree in history. He was researching his grandfather's WWI service when he stumbled upon Newhall's letters and papers in the archives at Williams College. After the war, Newhall spent decades as a history professor at the Massachusetts school.

Nelson uses the friendship between Newhall and Haydock as the spine of "Five Lieutenants," his second of three WWI books.

In some ways, their friendship was improbable. Newhall was a nerd with few friends, earning a Ph.D. in history at Harvard when America entered the war. Haydock, at 22, was six years younger, using his athletic gifts to became a pole vaulting star at Harvard. After college, he worked his way up to a desk job at a textile mill north of Boston.

"Newhall, ever the loner, in some ways saw the younger Haydock as a like-minded protégé, a gentler, more affable version of himself, and Haydock saw Newhall as a big brother figure," Nelson said. "Their friendship was intensified quickly by the uncertainties of war, and the fact each of them could have been killed almost at any moment."

Newhall called their bond a "most perfect" friendship. They played chess, acted out readings of "Macbeth" and took long walks through French villages. Both looked forward to the war's end so they could get on with their lives.

"Neither of us, I am sure, had any sort of military ambition," Newhall wrote, describing their shared disdain for "bawling-out soldiers" and the "professional bullying" known as the army way.

"We discovered our mutual compatibility and the extent to which we found moral support in each other. There was a quiet, spontaneous quality about our friendship which was unlike any other relationship I have experienced."

When they stepped into battle, Newhall didn't make it 10 steps before bullets pierced his right armpit and left arm. He would stay sprawled on the battlefield for 40 hours before walking in a crouch, with excruciating pain, back to his trench. That's where he learned his regiment had taken Cantigny — but that his best friend was dead.

"I went to pieces, and cried out, probably somewhat hysterically," he wrote.

Haydock, not far away, was directing his platoon when a German machine-gunner, hidden by a large beet pile, killed him instantly.

"It was a gallant end without sorrow or pain to him," Newhall wrote to Haydock's mother from a hospital a few months later. "And there have been times in the last six weeks when I thought of it a little enviously.

"George was very dear to me. His companionship made tolerable this military life which is very hateful to me. I shrink from the idea of returning to that life alone."

When he came home, Newhall's ongoing treatment for his wounds prevented him from spending Christmas in 1918 back in Minneapolis. So he stayed instead with Haydock's family in Massachusetts, sleeping in his friend's untouched bedroom.

Newhall never regained use of his left arm. Each May 28, he'd send roses to Haydock's parents. After they died, he sent flowers to his friend's sister until his own death in 1973, at 85.

While scouring Newhall's papers in the archives, Nelson found some scribbling about a dream Newhall experienced in 1967 — nearly 50 years after he last saw his friend. Nelson knew he had the end for his book.

"Last night I dreamed of George Haydock," Newhall wrote, insisting it had never happened before. "My memory of the dream is somewhat vague, but we seemed to be going somewhere together until we came to a place where I turned aside and he went on, and I kissed him on the cheek."

Curt Brown's tales about Minnesota's history appear each Sunday. Readers can send him ideas and suggestions at mnhistory@startribune.com. A collection of his columns is available as the e-book "Frozen in History" at startribune.com/ebooks.