Casio was established in April 1946 by Tadao Kashio, an engineer specializing in fabrication technology. The concept of the wristwatch goes back to the production of the very earliest watches in the 16th century. Elizabeth I of England received a wristwatch from Robert Dudley in 1571, described as an arm watch. From the beginning, wrist watches were almost exclusively worn by women, while men used pocket-watches up until the early 20th century. Casio made wristwatches worthwhile in the 20th century, when it was modernized to complement contemporary men and women.