Medieval French Measurements: From the Pope’s Nose to the Metric Revolution

Yes, you read that right. There was a time — before centimetres, before metres, even before the metric system was a twinkle in Napoleon’s eye — when the French measured things using, among other things, the Pope’s nose. Or, more accurately, a rumoured length based on said nose. Because, let’s be honest, why wouldn’t you standardise national infrastructure on the olfactory appendage of a distant religious figure?

Medieval French units of measurement were a riot of inconsistency, whimsy, and regional stubbornness. It’s a miracle anyone built anything taller than a haystack. Welcome to the truly flexible world of pre-metric French measurements, where one man’s foot was literally another man’s foot.

The Absurd Flexibility of Medieval French Measurements

Picture this: you’re in 13th-century Burgundy. You ask the local blacksmith for a six-foot-long iron bar. He nods — but his “foot” is not the Parisian foot. Nor the Lyonnais foot. It’s the local foot, which might be longer, shorter, or just whimsically defined by the size of the town elder’s shoe.

This chaos extended to all sorts of units: the pouce (inch), the toise (fathom), the aune (used for cloth), and of course, the infamous pied du pape — the Pope’s foot, or nose, depending on who you ask.

And because nothing says consistency like regional independence and personal anatomy, each of these could vary dramatically from town to town. A merchant from Marseille might think he’s selling a perfectly respectable barrel of wine, only to be told in Paris he’s short by half a local queue (yes, that’s a unit too).

Did They Really Measure by the Pope’s Nose?

Not officially — but the story holds symbolic truth. The “nose of the Pope” measurement seems to have originated more as a satirical commentary on the absurdity of using body parts for standardisation. In other words, if you’re already using a king’s forearm or a noble’s stride, why not go all in with the papal profile?

What was real, however, was the Pied du Roi — the King’s foot — which for a time became France’s most official, if still deeply arbitrary, unit. This royal foot was based on the actual foot of a monarch (because that’s how science worked back then), and was roughly 32.48 cm.

Still, jokes and jabs about measuring things by papal schnoz caught on. They highlight a very real frustration: the total lack of measurement consistency before the metric system came along to ruin everyone’s fun.

The Birth of the Metric System: Order from Nasal Chaos

By the late 18th century, France had had enough. Revolution was in the air, wigs were out, and Enlightenment thinkers were very done with everyone using different-sized feet.

In 1795, the newly formed French government officially adopted the metric system, an elegant, decimal-based system rooted in — wait for it — the Earth itself. The metre was originally defined as one ten-millionth of the distance from the equator to the North Pole along a meridian passing through Paris.

Which, yes, sounds complicated. But at least it wasn’t based on anyone’s nose.

The system introduced the metre, the kilogram, and eventually the litre. It was meant to be universal, scientific, and deeply French. It also made sure that measuring cloth in Avignon wouldn’t result in a shouting match with a tailor in Tours.

Travel Through France’s Measurement Mayhem

If you fancy geeking out on historic units (and honestly, why wouldn’t you?), here are a few places that turn measurement madness into fascinating travel stops:

Musée des Arts et Métiers – Paris

Housed in a former abbey, this museum is a playground for nerds of all flavours. Don’t miss the original platinum metre bar, created during the French Revolution to define the new standard. You’ll also find antique measuring devices, weight scales, and a deep dive into how Enlightenment thinkers dragged France out of the unit dark ages.

Château de Versailles – The Hall of Grandiose Guesswork

Before standardisation, palace architects were estimating based on glorified guesses. Versailles is a masterclass in “measure once, build forever,” using a mix of toises, pieds and royal whim. If you squint hard enough, you can almost see the confusion on the masons’ faces.

Musée de l’Histoire de la Médecine – Paris

Weird sidebar? Not really. Medical tools were sized and calibrated using all sorts of inconsistent units before metrication. It’s a reminder that medieval medicine wasn’t just dangerous — it was imprecise in every possible way.

Why This All Still Matters

Yes, we now live in a world of clearly defined SI units and strict calibration. But understanding the chaotic past of French measurements shows us just how far we’ve come — and how much politics, personality, and papal noses once influenced basic facts of life.

The metric system now rules most of the globe (sorry, Liberia, Myanmar, and the US). But buried beneath it is a colourful, gloriously ridiculous layer of history where units were more symbolic than scientific, and your location could change the length of your ruler.

Wild and Whimsical Old French Units You Probably Shouldn’t Use

Length and Distance

• Pied du Roi (foot) ≈ 32.48 cm
  (Slightly longer than an English foot, which is about 30.48 cm.)
• Pouce (inch) = 1/12 of a pied ≈ 2.707 cm
• Ligne = 1/12 of a pouce ≈ 2.256 mm
• Toise ≈ 1.949 metres
  (A toise is 6 pieds.)
• Aune (used for cloth) ≈ 1.188 metres
  (Highly regional: could vary from about 1.2m to 1.5m.)
• Perche (also called perche d’arpent) ≈ 3.898 metres
  (Used mainly in land measurement.)
• Lieue de poste (league, post road) ≈ 4.288 kilometres
  (But varied depending on the type: common lieues could range from 3.2km to 4.8km.)

Area

• Arpent (of Paris) ≈ 0.3419 hectares or 3,419 m²
  (Roughly similar to 0.845 acres.)
• Perche carrée (square perch) ≈ 15.20 m²
• Journal (field area that could be ploughed in one day) ≈ 0.32 hectares
  (Varied by region, but roughly a third of a hectare.)

Volume

• Pinte de Paris ≈ 0.931 litres
  (This is not the same as the modern UK pint!)
• Boisseau (grain measure) ≈ 12.7 litres
• Setier ≈ 156 litres
  (Larger dry measure; varied a lot by locality.)
• Muid (used for wine or grains) ≈ 268 litres
  (Again, heavily regional.)
• Litron ≈ 0.831 litres

Weight

• Livre de Paris (pound) ≈ 489.5 grams
  (Heavier than the modern metric half-kilo.)
• Once (ounce) = 1/16 of a livre ≈ 30.6 grams
• Grain (smallest unit) ≈ 53.1 mg
• Quintal ≈ 48.95 kg
  (100 livres.)
• Marc (often for weighing precious metals) ≈ 244.75 grams