For the first time, 21st-century audiences are able to hear the voice of Otto von Bismarck, one of the 19th century's most important figures.

The US National Park Service announced this week that the German chancellor's voice has been identified among those found on a dozen recorded wax cylinders, each more than 120 years old, that were once stored near Thomas Edison's cot in his West Orange, New Jersey, lab.

They include music and dignitaries, including the voice of the only person born in the 18th century believed to be available on a recording. The trove includes Bismarck's voice reciting songs and imploring his son to live morally and eat and drink in moderation.

"In the 18th century the human voice was described as one of the most noble capacities of human beings", Stephan Puille, the German researcher who identified Bismarck's voice, said.

"Bismarck is no longer mute. I think his voice allows a new access to him. Sound is three-dimensional. Heretofore we only knew Bismarck from pictures and drawings. Now we know him a little better," he said.

The people who study and collect early recordings knew they had been made, but did not know they still existed.

"Most early recordings I have read about had not survived," said Patrick Feaster, an Indiana University scholar who also helped crack the mystery of what was on the cylinders.

The recordings were made in 1889 and 1890 by Theo Wangemann, whom Edison sent to supervise the use of the Edison Phonograph Works machines on display at the Paris World's Fair in 1889 before travelling to his native Germany.

Mr Feaster describes Wangemann as "the first serious professional recording engineer". While in Paris, he recorded orchestras, pianists, a comedian and others and even recorded on the then-new Eiffel Tower.

While sound recordings were made as early as 1859, the ones on Edison's wax phonographs were in the first generation of recordings intended for playback.