The original inventor of the simple protractor is unknown. One of the first descriptions of the protractor appeared in a work released by Thomas Blundeville in 1589 describing it as a tool that is used to measure and draw angles.
The first complex, three-arm protractor was invented in 1801 by a U.S. naval captain named Joseph Huddart. The three-arm protractor featured a static center arm attached to two outer arms that can be rotated. This allows the two outer arms to be set at any relative angle to the static center arm. Protractors also come in plastic varieties with no movable parts.