BONN, Germany — The slightest hint that a lost manuscript, letter or personal artifact of the great German composer Ludwig van Beethoven might exist and be available for acquisition is enough to get Michael Ladenburger's adrenaline pumping.
The 60-year-old musicologist heads the Beethoven-Haus museum and is custodian of its collection, which includes one-third of all the extant original musical scores and 700 of the letters written by the composer. Hiring on in 1984 as scientific adviser to the archive, Ladenburger oversaw the museum's renovation soon afterward and was named chief in 1990.
But his job over the years has evolved into that of detective, applying his considerable forensic skills and his vast knowledge of the composer and his times to track down, verify and if possible acquire Beethoven documents and personal effects.
Although most original Beethoven documents are in archives or collections two centuries after his death — he lived from 1770 to 1827 — a few surface from time to time, and news of that is what gets Ladenburger's juices flowing.
This year, Ladenburger the "gumshoe" acquired an 1811 letter that Beethoven wrote to friend and patron Count Franz von Brunswick, who was the dedicatee of his famous "Appassionata" piano sonata. The museum had already acquired the envelope in 1995. "So it's a match."
A few months ago, Ladenburger acquired on permanent loan original silhouette cutouts dating from the 1780s of five members of the Von Breuning family, Beethoven's early sponsors in Bonn. He got both items directly from the sellers, to avoid paying a finder's fee. The same artist cut a silhouette of Beethoven at age 15, the earliest known portrait, which is also in the museum's collection.
"You have to know the right persons, you have to have a good nose, and you have to have luck," he said.
He was able to verify the Von Breuning cutouts, which were in the hands of the family's descendants and thought to have been lost during World War II, partly through their watermark, a sort of trademark used by paper mills. Using a reference book that catalogs watermarks from 200 years ago, he found that the silhouettes had been cut from paper made at the same mill near Amsterdam that produced the parchment on which the U.S. Declaration of Independence was written in 1776.
But it's Ladenburger's acquisitions of manuscripts that have affected Beethoven studies and performances. Recent buys include the drafts of two of Beethoven's 32 piano sonatas — Opus 90 and Opus 101 — and the original handwritten score of the Diabelli Variations, Beethoven's last major piano composition.
The documents are stored in a vault beneath the museum, in the house where Beethoven was born in Bonn and spent the first three years of his life.
"The Beethoven House and museum are a treasure in honor of a treasure," said Jan Swafford, a Tufts University music professor and composer whose biography "Beethoven: Anguish and Triumph" will be published in spring. "The collection of manuscripts, editions and publications add up to something unparalleled."
Acquiring original scores is important for Beethoven performers and devotees because careful revision often reveals publishing mistakes, Ladenburger said. And letters and personal effects give hints of the personality of one of Western culture's titanic figures, deepening listeners' understanding of the man.
Music critic and author Peter G. Davis said the museum's manuscripts serve the "scholarly importance of seeing precisely what the composer wrote," while Beethoven's personal effects, which include two pianos and several portraits in addition to private correspondence, "reinforce our humanity and closeness."
After the Diabelli Variations manuscript was acquired in 2009, several wrong notes were discovered in the standard transcription and changes have been made in recent recordings by leading Beethoven interpreters such as Hungarian pianist András Schiff, who performed the variations in Los Angeles in October.
An indication of the devotion some classical artists feel to Beethoven and to the museum was revealed in how Ladenburger financed the Diabelli Variations' multimillion-dollar purchase price. (Ladenburger won't disclose the amount.) The manuscript was paid for in part by a series of benefit concerts by world-class musicians including Schiff, violinist Anne-Sophie Mutter and conductor-pianist Daniel Barenboim.
"The importance of access to Beethoven's manuscripts and sketches is invaluable," pianist Schiff said in an emailed comment. "For me, studying, performing and recording the piano sonatas and the Diabelli Variations with the help of these sources has been a great inspiration, a privilege."
Unlike some archives that jealously keep their collections under wraps, Ladenburger has pushed for the digitalization of all the museum's Beethoven documents and to make them available to anyone via the museum's website. It's part of the museum's efforts, he said, to make classical music relevant to youth, a tough task in an age of vanishing orchestras, classical music radio stations and CD sales.