"I was very young, and it was really my first time away home," says Hrivnak, 38, of Bethel Park, who has served in both Gulf wars and began keeping a diary during his first mission in 1990.
"There was a lot of anxiety about the upcoming war that night on Christmas Eve," he says. "At our field hospital, some British mercenaries had sponsored this Christmas Eve for us. ... I still get choked up thinking about this: Some big, burly, gruff guy with a great baritone voice got up and sang ‘Silent Night,’ the ‘Star-Spangled Banner’ and Great Britain’s national anthem.
"I can still see everyone’s faces. There was not a dry eye in the room."
That year, he wrote to his mother to tell her that although he wanted to be home for Christmas, spending it at the field hospital was one of the best Christmases he ever had.
Since the beginning of the U.S. military, with the 1775 formation of the Continental Army by 13 colonies seeking independence from Great Britain, troops have kept diaries and sent letters home -- and their thoughts and emotions, especially at Christmas, are a constant spanning that time.
"The formality of the language is the only thing that has changed over the centuries or over the generations," said Washington, D.C.-based author Andrew Carroll, founder and director of the Legacy Project, an organization that preserves personal wartime correspondence.
"The emotions from war to war are exactly the same," said Carroll, who estimates he has read more than 80,000 letters spanning the French and Indian War to the Iraq war.
It makes no difference whether a soldier is hundreds of miles from home, as many were during the Civil War, or 10,000 miles away, in the Middle East, Carroll said. It's still far from home.
"They are missing the traditions and rituals of their family, so they write home about these fond memories as something to cling to -- it is what keeps them going."
Hrivnak's sentimentalism and yearning for home at Christmas is not much different from that of Civil War Capt. John W. Patterson, who noted on Dec. 29, 1861, in a letter to his wife, Armira, on display at Soldiers and Sailors Memorial Hall in Oakland: "I ... had pleasant thoughts of Home(cq) and the loved ones there."
Patterson, of Birmingham, which became Pittsburgh's South Side neighborhood, was with the 102nd Pennsylvania Volunteer Infantry, Company E, at Camp Tennallytown when he wrote to her: "I trust that you will not fret about me. I am well and enjoy military life hugely and besides that I expect to live through this war and get home to my family and there remain. Do not therefore my dear Armira grieve at my absence."
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