I want to know the answer to the following question:
When was the metric system officially introduced?
All the background I'm provided with is that "Napoleon ultimately took a retrograde step in 1812 when he passed legislation to introduce the mesures usuelles (traditional units of measurement) for retail trade—a system of measure that resembled the pre-revolutionary units but were based on the kilogram and the metre; for example the livre metrique (metric pound) was 500 g instead of 489.5 g—the value of the livre du roi (the king's pound).". Is that enough to answer the question?