03/20/2011 03:00 pm ET | Updated May 25, 2011

An American's Unique Link to German History

In the next day or two, a moving van will depart from a home in Chevy Chase, Md., bearing a unique cargo bound for New Haven, Conn., that marks the final chapter of a remarkable story covering nearly 200 years of German-American history as seen through the eyes of Thomas L. Hughes.

Hughes, a former top State Department official, diplomat and foundation president, has spent a lifetime adding to a massive collection of memorabilia begun by his great-great-grandfather that documents his family ties to the German and Prussian imperial dynasty, the Hohenzollerns, from the time of Frederick the Great and Kaiser Wilhelm I to Hitler's Third Reich.

Among the van's contents will be some 350 letters from Hohenzollern family to Hughes, including several from the former Kaiser himself, along with hundreds of commemorative coins; dozens of oil portraits and photographs, busts and vases; and even ivory tobacco boxes that Frederick the Great gave his generals during his 18th century wars.

The collection, appraised at $1 million, will be preserved at Yale University, where Hughes earned a law degree after graduating from Carleton College and winning a Rhodes Scholarship at Oxford. Earlier, Hughes shipped hundreds of maps and engravings and more than a thousand books from his Hohenzollern collection to Yale, some of them rare volumes dating back to the 16th century.

Perhaps as remarkable as the collection itself is the story behind it. The 85-year-old Hughes began researching the Hohenzollern family as a 12-year-old boy in 1938 while exploring the attic of his grandfather's house. What he found would change the course of his life.

"I asked my aunt, 'What's locked in the attic?,'" Hughes said in a recent interview as he recalled visiting his maternal grandfather's home in the small southern Minnnesota town of Pipestone, not far from his hometown of Mankato. "It was always locked and off limits and was a mystery to me, but she had the key so I went up and looked."

The attic contained a treasure trove of coins, books, statues and documents collected by his great-great-grandfather, Carl Friedrich Schlaberg, who left Germany in 1812 to avoid conscription in the French army when Napoleon invaded Russia. He emigrated to Scotland, then Canada in 1828, and, and finally, in 1879, four years before his death, to Minneapolis to live with a daughter.

The young Hughes was amazed to discover that he was related to the German imperial family, one of more than 300 Schlaberg descendants living in the U.S. at the time. The emigrant Schlaberg was a ninth generation descendant of Sigismund Brandenburg, who became Archbishop of Magdeburg at the age of 16 in 1554, and though an unmarried Catholic prelate, fathered a son in 1560 with a woman named Schlaberg, who took his mother's name.

Hughes speculates that his grandfather, Dr. Thomas Lowe, who was a physician and mayor of Pipestone, and later a member of the Minnesota legislature, kept the collection hidden away in his attic because of anti-German antipathy during World War I.

Young Hughes quickly acted on his discovery. He wrote several letters to surviving members of the Prussian royal family, many of whom wrote back, including the former Kaiser, Wilhelm II, his wife and five sons. Using the correspondence and researching historical records, he compiled a detailed family tree all the way back to the original Hohenzollern-Schlaberg union.

Emulating his grandfather, who wrote a history of Minnesota's Sioux Indians, young Hughes compiled the first of three volumes of history of the Hohenzollern family for a junior high school project that was featured in the Mankato newspaper, but broke off the correspondence when the U.S. declared war on Germany.

After the war, Hughes resumed contact with his German relatives, including the Kaiser's widow, who wrote in 1948 that she was under Russian house arrest in East Germany and "without a home, without my books, and without my possessions. I had to leave everything behind, when I left my Silesian castle." She accepted Hughes' offer to send her some sustenance, declaring, "Coffee would be a great help, and a little cocoa."

Hughes, who later served as an aide to Senator and Vice President Hubert Humphrey, assistant secretary of State for Intelligence and Research in the Kennedy and Johnson administrations, minister of the U.S. Embassy in London under President Nixon, and president of the Carnegie Endowment for International Peace, met many of his German relatives in the ensuing years.

Until now, Hughes' home has been a veritable museum, filled with oil portraits, photographs and busts of his ancestors, including one of his great-great-grandfather Schlaberg that hangs over a living room fireplace, and a large bust of German and Prussian Crown Prince Frederick William that he sent to Schlaberg in 1881. But all that will soon be on its way to Yale.

As Hughes told the Berliner Zeitung in July 2008 before deciding to give his collection to Yale, he was concerned that it not be separated and preserved in one place. "The only thing certain is that the treasures will not again be consigned to the attic," he told the newspaper.