Wolfgang Amadeus Mozart began his series of preserved piano concertos with four that he wrote in Salzburg at the age of eleven : K. 37 and 39–41. The autographs, all held by the Jagiellonian Library, Kraków, are dated by his father as having been completed in April and July of 1767. Although these works were long considered to be original, they are now known to be pasticcios of sonatas by various German composers. The works on which the concertos are based were largely published in Paris, and presumably Mozart and his family became acquainted with them or their composers during their visit to Paris in 1763–64.