On August 4, 1805, Irish physicist, astronomer, and mathematician William Rowan Hamilton was born. He made important contributions to classical mechanics, optics, and algebra, but is perhaps best known as the inventor of quaternions, a number system that extends the complex numbers.
On April 30, 1777, German mathematician and physical scientist Carl Friedrich Gauß was born. He who contributed significantly to many fields, including number theory, algebra, statistics, analysis, differential geometry, geodesy, geophysics, electrostatics, astronomy and optics. He is often referred to as Princeps mathematicorum (Latin, "the Prince of Mathematicians") as well as "greatest mathematician since antiquity".
On January 12, 1665, French lawyer and amateur mathematician Pierre de Fermat, famous for his research in number theory, analytical geometry and probability theory, passed away. He is best known for Fermat's Last Theorem, which he described in a note at the margin of a copy of Diophantus' Arithmetica.
On September 20, 1996, Hungarian mathematician Paul Erdös passed away. He published more scientific papers than any other mathematician in history, with hundreds of collaborators.