Howard Aiken designed and oversaw the construction of the Mark I, the first large-scale fully automatic digital computer, at Harvard University between 1944 and 1947. The Mark I was an electromechanical computer that was designed to perform complex mathematical calculations for the United States Navy's Bureau of Ships during World War II. It could add or subtract in less than one second and multiply or divide in less than three seconds, making it much faster than previous mechanical calculators for complex equations.