A fisherman pulled a beer bottle with the scribbled message out of the Baltic off the northern German city of Kiel last month. The postcard inside was tossed into the sea 101 years earlier.
"This is certainly the first time such an old message in a bottle was found, particularly with the bottle intact," Holger von Neuhoff of the International Maritime Museum in the northern port city of Hamburg told the European media.
Researchers then set to work identifying the author and managed to track down his 62-year-old granddaughter Angela Erdmann, who lives in Berlin.
"It was almost unbelievable," Erdmann told the German news agency DPA.