Robert Recorde was one of those people so extraordinarily ahead of his time that he seemed destined to come to a tragic end. In the 16th century, he made advances in economics, medicine, theology, and poetry. But his greatest contribution is taught to every elementary school child, and it arguably laid the groundwork for modern computer science. He invented the equals sign.
Recorde’s symbol didn’t catch on at first. The language of Latin still held sway during the 16th century. Latin had a word for the concept, “aequalis,” and if more concision was necessary, people could shorten it to “ae” or “oe.” But aiding the popularity of the equals sign was Recorde’s introduction, to English-speakers, of the German symbols “+” and “-“. In combination, these signs allowed people to express, quickly and with a minimum of wasted ink, a mathematical equation in symbols. Instead of writing, “A factore added to a quantitie of thryeye is equalle to a dyffyrynte factore frome whyche is takene awaye a quantitie of foure,” a mathematician could write: “x + 3 = y – 4”.