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Pre 1800

500 BC or so, Invention of the Counting Board

The picture to the right shows a modern abacus. In ancient times, these devices were very, very different. The abacus (or counting board, as these early devices are more properly known) evolved from a need for merchants to count their inventories, calculate prices and similar functions.

The original counting boards were made of wood, stone or metal, and had groves between which beads or pebbles were moved.

300 BC, The Salamis Tablet

The oldest know example of a counting board is called "The Salamis Tablet". It was used around 300 BC by the inhabitants of Babylonia, and was discovered in 1899 on the Island of Salamis. The board is made of marble, with rows and columns consisting of groves carved into the stone. There are Greek symbols carved into the top and bottom.

1000 AD Invention of Abacus (America)

Around 1000 AD the Aztec peoples invented a device similar to an abacus which used corn kernels threaded through wooden frames. This was known as a Nepohualtzitzin.

1200 AD Invention of Abacus (China)

The abacus as we know it was invented in China round 1200 AD, and it was known to the Chinese as suan-pan.

1500 AD Leonardo da Vinci's calculator

In roughly 1500 Ad, the famous inventor and painter Leonardo da Vinci drew a strange device (shown to the left) which was presumably a calculator. This is known as the Codex Madrid. In 1968 Dr. Roberto Guatelli built the device to see what it would do. There was much controversy associated with this replica, as it went far beyond the concepts of the drawing. The replica was displayed at the IBM exhibition, but was removed and is now lost.

1614 Invention of Logarithms

In 1614 a man by the name of John Napier (born 1550, died 1617) published a books called "Rabdologia". Napier was a very gifted and intelligent mathematician, and his invention enabled people to transform complex multiplication and division into simple addition and subtraction.

1650 Invention of Slide Rule

The first Slide Rule appeared in 1650 and was the result of a joint effort of two Englishmen Edmund Gunter and the reverend William Oughtred. This slide rule based on Napier's logarithms was to become the first analog computer (of the modern ages) since multiplication and subtraction were figured out by physical distance. This invention was dormant until 1850 when a French Artillery officer Amedee Mannheim added the movable double sided cursor, which gave it it's appearance as we know it today.

Invention of Mechanical Calculator

A man named Blaise Pascal invented the first digital calculator between 1642 and 1645. He probably created the device to help his father with his work collecting taxes.