The 75th anniversary of D-Day reminds me of the most valuable history lesson I ever learned and the man who taught it to me.

In 1995 I was a first-year high school social studies teacher in Duluth. One day I returned to my classroom after lunch to find a bundle of papers on my desk, along with a handwritten note from my principal. Mr. McGee was passing along the transcription of a journal he obtained from a relative because he thought it might help bring World War II to life for a bunch of students in Minnesota.

Intrigued by what was inside, I made my way that summer to a tiny farm community in Hubbard County, hoping to discover more about one man's past and perhaps an inspiring example upon which to build my future. I found both.

Months before arriving at Normandy in 1944, 21-year-old Virgil Tangborn of Nary, Minn., had begun to record his daily experiences. His journal survives 75 years later and helps make that era seem closer, more real.

Though I never met him, Virgil taught me what courage means and for that he is my hero.

Interspersed with observations about farm life and about events halfway around the world, Virgil's words reflect the inner struggle of a man determined to plan his future despite the growing likelihood that his fate was beyond his control. He wrote:

December 10, 1941: "This has been one of those days when I have completely relaxed my will and just drifted, following almost every impulse, living hour by hour … Last Sunday Japan attacked in the Pacific and brought U.S. into war. This makes an army life for me extremely probable. Must face it with resolution to do my best to adjust myself to such a life.

January 25, 1942: "Began this afternoon to form new, more energetic habit of life — to root out that put-off-until-tomorrow philosophy."

March 24, 1942: "Warm, mild, spring-like. Military life grows more near. Black despair at prospect. Reading books and taking it very easy. No will to work. Reading 'Brothers Karamazov' today. Discussing future tonight with Father. He advises 'educational' work. That's where I've often suspected my interests and talents (if any) lay. But my ideas and desires are vague and unsure on this score. I have a desire which I hardly admit to myself — to be an artist of some kind. Motion pictures — Novelist, but I probably haven't the slightest talent."

March 26, 1942: "Next Tuesday I leave for Fort Snelling for physical exam. Hope I don't pass it for very justified reasons. But hardly dare hope … Man should strive to enrich as much as possible life. To make himself an important tool in the general progress of mankind."

March 27, 1942: "A strange calm has come over my feelings and disposition last two days. Feel a strong will to achieve something forming and growing. It seems like I have been living a too careless and too easy a life … Maybe I am squarely facing reality at last and am beginning to mature mentally."

March 30, 1942: "Tomorrow leave for army life if I'm not rejected for physical reasons … This will be my last day for recording until the present ordeal is over. Maybe I'll be back by the end of week, maybe end of decade."

Courage is, as Virgil understood, forsaking one's future to become a "tool in the general progress of mankind."

He was killed eight days after D-Day, trying to save a wounded truck driver whose vehicle had been struck by Nazi artillery.

Risking life and limb in the heat of battle takes guts. Abandoning the relative tranquility of northern Minnesota to help turn the tide of history requires remarkable courage. Virgil Tangborn had both.

I have shared Virgil's story with hundreds of students over the intervening 24 years. While I'm not sure how much inspiration they gain from it, I know the ordinary nature of Virgil's words combined with the extraordinary act of giving his life that others might live represents the ultimate expression of love.

Virgil mused privately about becoming a teacher one day. He was one and still is.

Steve Werle lives in Minneapolis. He is the author of "Stassen Again," a 2015 book about Minnesota's World War II-era governor Harold Stassen.