Simon Stevin (1548-1620) was a Dutch mathematician, mechanician and physicist. He was born in Bruges (now Belgium). In 1571 — 81 he travelled in Europe. From 1581 he lived in Leiden, Delft and The Hague. From 1583 he taught at the University of Leiden, from 1592 he was an engineer and superintendent to Maurice of Orange, and in 1620 he organised an engineering school at the University of Leiden, where he lectured on mathematics.
He was the first to formulate the theorem of the triangle of forces, gave a new proof of the law of equilibrium of forces on an inclined plane, based on the impossibility of perpetual motion, and proposed a way of representing forces by lines. He was the author of “The Elements of Statics” (1586). He formulated the law of hydrostatic pressure. He introduced the concept of the metacentre. He studied the magnetism of the Earth.
He brought decimal fractions, negative roots of equations and the like into use in Europe.