The history of IQ testing started about 100 years ago, up to that point the terms like "IQ“ or "IQ test“ were not widely used. The work intelligence comes from Latin and initially it did not have the meaning relating to an individual's ability to solve tasks, it related to the brain and its ability to deal with mental questions.
The situation changed significantly in 19th century with the emergence of psychology. In 1890 psychologist James McKeen Cattell for the first time used the term "test" in connection with human intellect. However, the real testing still had to wait. It only started in 1890 with Simon and Binet and their Binet-Simon test that is so important for the history of measuring intelligence. Binet and Simon work was in 1912 taken further by the German psychologist William Stern who additionally included both the mental and chronological ages and introduced the term "intelligence quotient" defined as: IQ = mental age / chronological age x 100.