On today's date in 1829, the German composer Felix Mendelssohn was in London, participating in a gala concert to raise funds for the victims of a flood in Silesia. "Everyone who has attracted the slightest attention during the season will take part," wrote Mendelssohn. "Many offers of good performers have had to be declined, as the concert, even so, will last till the next day!"

Mendelssohn performed his Double Concerto in E Major for two pianos and orchestra, joined at the second piano by his friend and fellow-composer Ignaz Moscheles. While rehearsing for the concert, Mendessohn and Moscheles jointly prepared a special cadenza, and jokingly bet each other how long the audience would applaud it—Mendessohn predicting 10 minutes, and Mosceheles, more modestly, suggesting 5.

In the Baroque age, Double Concertos were very popular, but by Mendelssohn's day they had become less common. In our time, Concertos for Two Pianos are even rarer. One of the most successful American Double Concertos was written between 1952 and 1953 by the American composer Quincy Porter. Also known as the "Concerto Concertante," this music was commissioned by the Louisville Orchestra, and premiered by piano soloists Dorothea Adkins and Ann Monks. It proved to be one of the most popular of Porter's works, and even won the Pulitzer Prize for Music in 1954.