Willebrord Snellius, also known as Snell, was a Dutch mathematician and astronomer born in 1580. He is best known for formulating Snell's Law, which describes how light bends when it passes through different media. This principle is fundamental in the study of optics and has applications in various fields, including physics and engineering. In addition to his work in optics, Snellius contributed to mathematics, particularly in trigonometry and geometry. He was also involved in cartography and helped improve the accuracy of maps during his time. Snellius passed away in 1626, leaving a lasting impact on science and mathematics.