The fortepiano that Mozart played almost daily for nine years will stand in his former Vienna home, now a museum, for two weeks, culminating in a concert of Mozart works.

Mozart bought the instrument from Anton Walter, the most famous Viennese piano maker of his time, in 1782. The prolific composer wrote more than 50 works for the fortepiano on it, many of them in the apartment on Vienna's Domgasse.

Mozart and his wife Constanze lived in the grand apartment in the shadow of St Stephen's Cathedral, where they married, at the height of Mozart's fame as a composer and soloist.

Towards the end of the decade, he became impoverished as the ability of his aristocratic patrons to support music was sapped by the Austro-Turkish war, and he was forced to move to the suburbs, taking his piano with him.

After Mozart's death, Constanze gave the instrument to their eldest surviving son, Carl Thomas, who donated it to the then Cathedral Music Association and Mozarteum on what would have been the composer's 100th birthday.

The piano is now part of the permanent exhibition at the Mozart family home in the Austrian city of Salzburg.

"It was very hard to let it go," Matthias Schulz, director of the Mozarteum Salzburg, told journalists. "If we didn't know it was in the best hands, we wouldn't have done it."

The fortepiano is much smaller and lighter than modern concert pianos, weighing just 85 kg (187 pounds) and measuring 1 by 2.23 metres (3 feet 3 inches by 7 feet 4 inches).

Its sound is fresher and brighter than that of a modern piano, with lighter action and hammers, but fades faster.

Piano restorer Josef Meingast, who has looked after the Mozart piano since 1975, said it was superior to any of its surviving contemporaries or copies. "The Mozart piano is the best by a long way," he told Reuters.

Meingast said he had to fight to replace the existing strings, dating from a 1973 restoration, with softer ones that produce a rounder sound thought to be more similar to what Mozart would have produced.

"The instinct of the museum people is to keep everything original as far as possible. They get a bad conscience if they chance something. But this instrument is for playing, not just a museum piece," he said.

Russian pianist Alexander Melnikov, who will give a concert of Mozart's music on the fortepiano on November 7, said he was privileged to play such an instrument.

"The emotional implications of such an experience are overwhelming," he said. "It's easily the biggest day of a musician's life." (Reporting by Georgina Prodhan, editing by Paul Casciato)

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