French history myths: The French invented the metric system of measurement

Myth: The French first invented the metric system and adopted it into general use after the Revolution in 1799.

The French were indeed the first nation to formally adopt the metric system and to standardise its measures - but they did not in fact invent it.

The metric or decimal system was first known as the 'system of the tenth' and its appeal is its simplicity - everything is easily divisible by 10.

So 100 centimetres equal one metre, 1,000 millilitres equal one litre and 1,000 grams equal one kilogram. 

When you look at the systems of weights and measures that were in place prior to the metric system, really the wonder is that it took someone so long to come up with such a simple system.

Each country had its own measurements and even the modern imperial system creates something of a mathematical challenge - for example in UK imperial measures there are 5,280 feet in a mile, 20 fluid ounces in a pint and 2,240 pounds in a ton.

The pre-metric system in France was particularly complicated and by 1789 there were at least 800 different units of measurement, many of which varied according to which town you were in or the type of trade you were trying to conduct.

The metric concept itself is generally credited to the Flemish mathematician, scientist and musician Simon Stevin (sometimes called Stevinus) who in 1586 published a pamphlet called De Thiende (the tenth) which lays out the principles of modern decimals.

His ideas were widely circulated around Europe in academic circles and by the mid-18th century more and more people were calling for standardised weights and measures between countries - primarily to help international trade.

In France a scientific committee had been set up before the revolution to look into the issue of weights and measures and in 1795 formally defined six units of metric measurement

• The mètre to measure length (defined as one ten-millionth of the distance between the North Pole and the Equator through Paris)
• The are to measure land (100 metres square) 
• The stère to measure volumes for firewood (1 cubic metre)
• The litre to measure liquid
• The gramme to measure mass
• The franc (for currency).

In 1799 these measures were formally adopted as the official units of measurement in France and the first 'kilogram' was made - a platinum weight that defined the new measure and is still in the French national archives.

It took about 50 years for the full transition to be made, although some of the old unit names remained in use, and once adopted other countries rapidly followed suit.

The metric system is now used in almost all the countries of the world, with the notable exceptions of the UK, the USA and Canada.

This article is part of our August series on popular myths and misconceptions about French history.