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".