University of Minnesota dental student Robert Ostergren was so miserable he couldn't sleep. So he wrote another of his countless letters to Esther Eldora Anderson, whom he would secretly marry on Sept. 7, 1921, in Albert Lea — 100 years ago on Tuesday.

"Esther I say in all frankness that this University life does not agree with me," he wrote. The university, he continued, "is the center of learning and here we are supposed to find civilization at its best but the more educated folks get these days it seems the more they want to get ahead of their fellow men by fair means or foul."

Ostergren went on to complain: "The days are full of disappointments and this reacts on the mind and keeps a person from getting a good night's rest." Cutthroat academia led to burnout, and he admitted to Esther: "I don't thrive shut in between four walls and sometimes it drives me nearly wild to sit down and try to plug along when I can't get interested in the work."

Esther, the oldest of five siblings, would quit her job at a railroad office to care for her invalid mother on St. Paul's East Side, where her father worked as a stone mason and built many of the fireplaces and chimneys around Lake Phalen.

A century later, granddaughter Lesley Ernst of Apple Valley has preserved Grandpa Rob's courtship letters, Esther's "Bridal Memories" book and an old newspaper clipping — all providing clues to their secret elopement in Albert Lea.

According to the bridal book, Rob and Esther were engaged after church services on Christmas morning 1919. They announced their marriage to surprised family and friends at a dinner party at her parents' East Side home on May 12, 1923 — one year and eight months after they had legally wed.

"I believe they eloped because getting married while in dental school was frowned upon," said Ernst, 62, a recently retired special education teacher. "But Grandpa was ready to give dental school up because he wanted so badly to marry Grandma."

Under a headline proclaiming "St. Paul Couple Jolt Relatives by Baring Wedding Held in 1921," a St. Paul Pioneer Press story said that their brothers and friends gasped when the couple finally broke their silence about getting hitched.

The guests had already been taken off guard by neatly written invitations to a Saturday night dinner party at the Anderson home on Hyacinth Street in honor of Rob and Esther's marriage.

"So one and all hotfooted it to the dinner with their eyebrows in the air," according to the Pioneer Press story. After all, the couple "were supposed to be nothing worse than engaged."

Father of the bride Aron Anderson said, "Take a look at this," and pulled out the marriage license from Albert Lea dated Sept. 7, 1921. "Every one talked at once and said why the very idea, Esther, and you certainly put one over that time Robert."

The article pointed to three possible factors behind the secrecy: Esther didn't want to leave home before her mother, Swedish-born Sarah Kate Anderson, died — which she did 17 months after the legal marriage, but three months before the big reveal.

Factor No. 2: "Robert thought he'd better get a little farther along toward his diploma before blossoming out with a better half." The third reason? The pranksters in love "both thought it would be a fine idea to put it over on their numerous brothers, eight all told."

The story: Rob and Esther were on their way to visit some Ostergren relatives in the southern Minnesota town of Bricelyn in September 1919 when they bumped into a family friend, the Rev. Arthur Hoag, in Albert Lea.

"So Robert and Esther just decided that then was as good a time as any other, and went ahead and jumped in," the Pioneer Press reported.

Ernst said Grandpa Rob got over his dental school burnout and went into practice. The township of Vadnais Heights gave the couple land near what would become the northeast corner of Hwy. 61 and Interstate 694, on condition he'd perform dentistry "out in the country," which Ernst said he did in addition to opening an East Side office on Payne Avenue.

Rob and Esther had two children, Alyce and Robert, who have both died. Ernst said she's "smack dab in the middle" of Rob and Esther's nine grandkids born from 1954 to 1969.

"I think [Grandpa Rob] wanted to be a naturalist or a poet but that's not what his family expected of him," said Ernst, who enjoys the flowery accounts of nature in his surviving letters.

"He and Grandma used to teach us about the animals and wildflowers in the woods and the creek on the land" near their Vadnais Heights property, Ernst said. "I had a special daisy patch where I would go and pick daisies. We have lots of good memories of the natural world where they lived."

Rob died at 65 in 1962 and Esther joined him a decade later, passing away in 1973 at 78. They were married 41 years — 39 of them in the open — and are buried together in Maplewood's Union Cemetery.

Curt Brown's tales about Minnesota's history appear each Sunday. Readers can send him ideas and suggestions at mnhistory@startribune.com. His latest book looks at 1918 Minnesota, when flu, war and fires converged: strib.mn/MN1918.