The pioneers

Some of the greatest people in European scientific history are involved in this affair. Admittedly, there are others, who attempted to create such devices, but nothing had survived to our time, e.g. the Dutch Jesuit-mathematician Jan Ciermans (1602-1648), who mentioned in a 1640 book, Annus Positionum Mathematicarum, that he created a mechanical calculator with iron wheels, suitable for multiplication and division.

Leonardo da Vinci (1493)

Wilhelm Schickard (1623)—the Calculating Clock

Blaise Pascal (1642)—the Pascaline

Tito Livio Burattini (1659)

Samuel Morland (1669)

Claude Perrault (around 1670)

Gottfried Wilhelm Leibniz (1672)—the Stepped Reckoner

René Grillet de Roven (1673)

Since we cannot know all that there is to be known about anything,
we ought to know a little about everything.
Blaise Pascal