Mathematics Throughout History

Development Ofweights and Measures

Who developed the idea of a foot in measurement?

There is quite a mystery about who first developed the idea of the foot as a measurement unit. One story, which most scholars believe is a legend, is that a foot was the length of Charlemagne’s (742–814) foot. Charlemagne (also known as Charles the Great) was King of the Franks and Emperor of the Holy Roman Empire. Standing at six feet four inches tall, he probably had a really big foot.

Still another story involves England’s King Henry I (1068–1135), in which an arm became important. The king ruled that the standard “foot” would be one-third of his 36-inch long arm. This thus became the origin of our standardized unit of 12 inches equals a foot, the inch being 1/36th of a yard. According to the Oxford English Dictionary, the first confirmed usage of the word “foot” as a unit of measurement also occurred during the reign of Henry I. In honor of his arm, he ordered that an “Iron Ulna” (the ulna being the longer, inner bone in the forearm) be made. This iron stick represented the master standard yard for the entire kingdom.

But around 1324, in response to his subjects’ cries for an even more standard measurement, England’s King Edward II (1284–1327) changed things again. Recognizing the “Iron Ulna” was not universally available, he declared that “3 barleycorns, round and dry make an inch,” and 12 inches (or 36 barleycorns) would equal one foot.

It’s interesting to note: Even shoe sizes were tied to King Edward II and barleycorns. He declared that the difference between one shoe size to the next was the length of one barleycorn.


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