When was the metric system of units introduced ?

The French originated the metric system of measurement (now called the International System of Units and abbreviated SI, pronounced ess-eye). Early development. Most historians agree that Gabriel Mouton, the vicar of St. Paul's Church in Lyons, France, is the “founding father” of the metric system. read more

1795–04–07: A law (La loi du 18 Germinal an III) was passed by the French Republic defining the metric system. 1799–12–10: France officially adopted the use of the metric system. read more

The concept of coherence was only introduced into the metric system in the third quarter of the 19th century; in its original form the metric system was non-coherent—in particular the litre was 0.001 m 3 and the are (from which the hectare derives) was 100 m 2. read more

The SI unit of area is the square metre (m 2), but when the metric system was first introduced in 1795, the unit of land measure was defined as the are, being 100 m 2 (or the area equivalent to that of a square having sides of 10 m). read more