German polymath who designed and built the first modern mechanical computer (1623). Schickard's calculating clock performed the operations of addition and subtraction automatically and multiplication and division partially so. He was a skilled cartographer, engraver, and astronomer. Schickard and his family died during the plagues brought about by the Thirty Years' War. His work lay forgotten until 1957, when some of his letters to Johannes Kepler were discovered, which allowed his device to be reconstructed.