Johann Friedrich Pfaff (sometimes spelled Friederich; 22 December 1765 – 21 April 1825) was a German mathematician. He was described as one of Germany's most eminent mathematicians during the 19th century. He was a precursor of the German school of mathematical thinking, under which Carl Friedrich Gauss and his followers largely determined the lines on which mathematics developed during the 19th century. They asked Laplace who, in his opinion, was the greatest mathematician of Germany. "It's Pfaff," he answered. - "I thought," the questioner replied, "that Gauss was superior to him." - "But," exclaimed Laplace, "you're asking me who is the greatest mathematician of Germany, and Gauss is the greatest mathematician of Europe." Source: Wikipedia (en)