Foot (unit)

==Historical origin==
{{See also|pous}}
[[File:Determination of the rute and the feet in Frankfurt.png|thumb|Determination of the rod, using the length of the left foot of 16 randomly chosen people coming from church service. Woodcut published in the book {{lang|de|Geometrey}} by [[Jakob Köbel]] (Frankfurt, {{c.|1535}}).]]
Historically, the human body has been used to provide the basis for units of length.<ref name="Dilke1987-23">{{cite book|author=Oswald Ashton Wentworth Dilke|author-link=Oswald A.W. Dilke|title=Mathematics and measurement|url=https://archive.org/details/bub_gb_AKJZvXOS7n4C|access-date=February 2, 2012|date=May 22, 1987|publisher=University of California Press|isbn=978-0-520-06072-2|page=[https://archive.org/details/bub_gb_AKJZvXOS7n4C/page/n23 23]}}</ref> The foot of an adult European-American male is typically about 15.3% of his height,<ref>{{cite journal
 |url         = http://www.sscnet.ucla.edu/anthro/faculty/fessler/pubs/AHBFootSizeDimorphism.pdf
 |title       = Sexual dimorphism in foot length proportionate to stature
 |first1      = Daniel M
 |last1       = Fessler
 |first2      = Kevin J
 |last2       = Haley
 |first3      = Roshni D
 |last3       = Lal
 |journal     = Annals of Human Biology
 |date        = January–February 2005
 |volume      = 32
 |issue       = 1
 |pages       = 44–59
 |doi         = 10.1080/03014460400027581
 |pmid = 15788354
 |s2cid = 194735
 |url-status  = dead
 |archive-url  = https://web.archive.org/web/20110608084140/http://www.sscnet.ucla.edu/anthro/faculty/fessler/pubs/AHBFootSizeDimorphism.pdf
 |archive-date = June 8, 2011
|df          = mdy-all
}}</ref> giving a person of {{convert|175|cm|ftin|abbr=on}} a foot-length of about {{convert|268|mm|abbr=on}}, on average.<!-- Stature chosen here as that of average Caucasian male. Edge cases may have too many other anomalies to be useful. -->

Archaeologists believe that, in the past, the people of [[Ancient Egyptian units of measurement|Egypt]], [[Indian units of measurement|India]], and [[Ancient Mesopotamian units of measurement|Mesopotamia]] preferred the [[cubit]], while the people of [[Ancient Rome|Rome]], [[Ancient Greece|Greece]], and [[Chinese units of measurement|China]] preferred the foot. Under the Harappan linear measures, Indus cities during the Bronze Age used a foot of {{convert|13.2|in|0}} and a cubit of {{convert|20.8|in|0}}.<ref>Kenoyer JM (2010) "Measuring the Harappan world," in Morley I & Renfrew C (edd) The Archaeology of Measurement, 117; {{cite web |url=http://a.harappa.com/sites/g/files/g65461/f/Kenoyer%202010%20Measuring%20the%20Harappan%20World.pdf |title=Archived copy |access-date=January 11, 2015 |url-status=dead |archive-url=https://web.archive.org/web/20150626134828/http://a.harappa.com/sites/g/files/g65461/f/Kenoyer%202010%20Measuring%20the%20Harappan%20World.pdf |archive-date=June 26, 2015  }}</ref> The [[Ancient Egyptian units of measurement|Egyptian]] equivalent of the foot—a measure of four palms or 16 digits—was known as the {{lang|egy-Latn|djeser}} and has been reconstructed as about {{convert|30|cm|abbr=on|1}}.

The Greek foot ({{lang|grc|πούς}}, {{lang|grc-Latn|pous}}) had a length of {{sfrac|600}} of a [[Stadion (unit of length)|stadion]],<ref>{{cite web|url=https://archive.org/details/historyofherod02hero|title=History of Herodotus : a new English version|last1=Herodotus|first2=George|last2=Rawlinson|date=May 14, 1861|publisher=New York D. Appleton|via=Internet Archive}}</ref> one stadion being about {{convert|181.2|m|abbr=on}};<ref>{{cite web|url=https://www.perseus.tufts.edu/hopper/artifact?name=Epidauros,+Stadium&object=Building|title=Epidauros, Stadium (Building)|website=www.perseus.tufts.edu|url-status=live|archive-url=https://web.archive.org/web/20170510073158/http://www.perseus.tufts.edu/hopper/artifact?name=Epidauros%2C+Stadium&object=Building|archive-date=May 10, 2017}}</ref> therefore a foot was, at the time, about {{convert|302|mm|abbr=on|1}}. Its exact size varied from city to city and could range between {{convert|270|mm|abbr=on|1}} and {{convert|350|mm|abbr=on|1}}, but lengths used for temple construction appear to have been about {{convert|295|mm|abbr=on|1}} to {{convert|325|mm|abbr=on|1}}; the former was close to the size of the Roman foot.

The standard [[Roman foot]]  ({{lang|la|pes}}) was normally about {{convert|295.7|mm|abbr=on|1}} (97% of today's measurement),<ref name=brit>Hosch, William L. (ed.) (2010) [https://books.google.com/books?id=cuN7rH6RzikC ''The Britannica Guide to Numbers and Measurement''] New York, NY: Britannica Educational Publications, 1st edition. {{ISBN|978-1-61530-108-9}}, p.206</ref> but in some provinces, particularly [[Germania Inferior]], the so-called {{lang|la|pes Drusianus}} (foot of [[Nero Claudius Drusus]]) was sometimes used, with a length of about {{convert|334|mm|abbr=on|1}}. (In reality, this foot predated Drusus.)<ref name="Dilke1987-26">{{cite book|author=Oswald Ashton Wentworth Dilke|author-link=Oswald A.W. Dilke|title=Mathematics and measurement|url=https://archive.org/details/bub_gb_AKJZvXOS7n4C|access-date=February 2, 2012|date=May 22, 1987|publisher=University of California Press|isbn=978-0-520-06072-2|page=[https://archive.org/details/bub_gb_AKJZvXOS7n4C/page/n26 26]}}</ref><ref>{{Cite journal |last=Duncan-Jones |first=R. P. |date=1980 |title=Length-Units in Roman Town Planning: The Pes Monetalis and the Pes Drusianus |url=https://www.jstor.org/stable/525675 |journal=Britannia |volume=11 |pages=127–133 |doi=10.2307/525675|jstor=525675 |s2cid=164149478 }}</ref>

Originally both the Greeks and the Romans subdivided the foot into 16 [[Digit (unit)|digits]], but in later years, the Romans also subdivided the foot into 12 {{lang|la|unciae}} (from which both the English words "inch" and "[[ounce]]" are derived).

After the fall of the Roman Empire, some Roman traditions were continued but others fell into disuse. In AD 790 [[Charlemagne]] attempted to reform the units of measure in his domains. His units of length were based on the {{lang|fr|[[toise]]}} and in particular the {{lang|fr|toise de l'Écritoire}}, the distance between the fingertips of the outstretched arms of a man.<ref>{{cite web
 |url         = http://www.unc.edu/~rowlett/units/dictT.html
 |author      = Russ Rowlett
 |publisher   = Center for Mathematics and Science Education, [[University of North Carolina at Chapel Hill]]
 |title       = How Many? A Dictionary of Units of Measurement
 |access-date  = February 28, 2011
|url-status     = live
 |archive-url  = https://web.archive.org/web/20121224005450/http://www.unc.edu/~rowlett/units/dictT.html
 |archive-date = December 24, 2012
|df          = mdy-all
}}</ref> The {{lang|fr|toise}} has 6 {{lang|fr|pieds}} (feet) each of {{convert|326.6|mm|abbr=on|1}}.

He was unsuccessful in introducing a standard unit of length throughout his realm: an analysis of the measurements of [[Charlieu Abbey]] shows that during the 9th century the Roman foot of {{convert|296.1|mm|abbr=on}} was used; when it was rebuilt in the 10th century, a foot of about {{convert|320|mm|abbr=on|1}}<ref group = "Note" name="cm">The original reference was given in a round number of centimeters.</ref> was used. At the same time, monastic buildings used the Carolingian foot of {{convert|340|mm|abbr=on|1}}.<ref group = "Note" name="cm"/><ref>{{cite journal
|jstor = 987740
|first = Elizabeth R
|last = Sutherland
|journal = Journal of the Society of Architectural Historians
|title = Feet and dates at Charlieu
|date = May 1957
|volume = 16
|issue = 2|pages = 2–5
|doi = 10.2307/987740
}}</ref>

The procedure for verification of the foot as described in the 16th century posthumously published work by [[Jacob Köbel]] in his book {{lang|de|Geometrei. Von künstlichem Feldmessen und absehen}} is:<ref>{{cite book
 |url         = http://www.robweir.com/blog/2007/12/right-and-lawful-rood.html
 |title       = Geometrei. Von künstlichem Feldmessen und absehen
 |year        = 1535
 |author      = Jacob Koebel
 |language    = de
 |url-status     = live
 |archive-url  = https://web.archive.org/web/20111116021207/http://www.robweir.com/blog/2007/12/right-and-lawful-rood.html
 |archive-date = November 16, 2011
|df          = mdy-all
 |author-link = Jacob Koebel
}}</ref><ref>{{cite web |title=Geometrey |url=https://digital.slub-dresden.de/werkansicht/dlf/8082/1/cache.off |website=digital.slub-dresden.de |publisher=Saxon State Library |access-date=February 22, 2019 |language=de-DE}}</ref>
{{blockquote|Stand at the door of a church on a Sunday and bid 16 men to stop, tall ones and small ones, as they happen to pass out when the service is finished; then make them put their left feet one behind the other, and the length thus obtained shall be a right and lawful [[Rood (unit)#Linear measure|rood]] to measure and survey the land with, and the 16th part of it shall be the right and lawful foot.}}

===England===
[[File:Imperial measurement standards, Greenwich.JPG|thumb|The unofficial public [[imperial units|imperial measurement]] [[standard (metrology)|standards]] erected at the [[Royal Observatory, Greenwich|Royal Observatory]] in [[Greenwich, England|Greenwich]] in the 19th century]]
{{See also|Yard}}

The [[Neolithic]] '''long foot''', first proposed by archeologists [[Mike Parker Pearson]] and Andrew Chamberlain, is based upon calculations from surveys of [[Stonehenge#Stonehenge 1 (c. 3100 BC)|Phase 1 elements at Stonehenge]]. They found that the underlying diameters of the stone circles had been consistently laid out using  multiples of a base unit amounting to 30 '''long feet''', which they calculated to be 1.056 of a modern [[#International foot|international foot]] (thus 12.672 inches or 0.3219 m). Furthermore, this unit is identifiable in the dimensions of some stone [[lintels]] at the site and in the diameter of the "southern circle"  at nearby [[Durrington Walls]]. Evidence that this unit was in widespread use across southern Britain is available from the [[Folkton Drums]] from  [[Yorkshire]] ([[neolithic]] artifacts, made from chalk, with circumferences that exactly divide as [[integers]] into ten long feet) and a similar object, the [[Lavant drum]], excavated at [[Lavant, West Sussex|Lavant]], Sussex, again with a circumference divisible as a whole number into ten long feet.<ref>{{cite journal |last1=Teather |first1=Anne |display-authors=etal|title=Getting the Measure of Stonehenge |journal=[[British Archaeology]] |date=February 8, 2019 |issue=165 |pages=48–51}}</ref>

The measures of [[Iron Age Britain]] are uncertain and proposed reconstructions such as the [[Megalithic Yard]] are controversial. Later [[Welsh legend]] credited [[Dyfnwal Moelmud]] with the establishment of [[Welsh units|their units]], including a foot of 9 inches. The Belgic or North German foot of {{convert|335|mm|abbr=on|1}} was introduced to England either by the [[Belgae|Belgic Celts]] during their invasions prior to the Romans or by the [[Anglo-Saxons]] in the 5th and 6th century.

[[Roman units]] were introduced following [[Roman conquest of England|their invasion]] in AD&nbsp;43. Following the [[Roman withdrawal from Britain|Roman withdrawal]] and [[Saxon invasion of England|Saxon invasions]], the Roman foot continued to be used in the construction crafts while the Belgic foot was used for land measurement. Both the Welsh and Belgic feet seem to have been based on multiples of the [[barleycorn (unit)|barleycorn]], but by as early as 950 the English kings seem to have (ineffectually) ordered measures to be based upon an iron yardstick at [[Winchester]] and then [[London]]. [[Henry I of England|Henry I]] was said to have ordered a new standard to be based upon the length of his own arm and, by the {{circa|lk=no|1300}} Act concerning the [[Composition of Yards and Perches]]<ref name="Britain1762">{{cite book|author=Great Britain|title=The statutes at large: from the Magna Charta, to the end of the eleventh Parliament of Great Britain, anno 1761 (continued to 1807)|url=https://books.google.com/books?id=iPQuAAAAIAAJ&q=Compositio+ulnarum+et+perticarum&pg=PA400|access-date=November 30, 2011|volume=1|year=1762|publisher=Printed by J. Bentham|page=400}}</ref> traditionally credited to [[Edward I of England|Edward&nbsp;I]] or [[Edward II of England|II]], the statute foot was a different measure, exactly {{sfrac|10|11}} of the old (Belgic) foot. The [[barleycorn (unit)|barleycorn]], [[inch]], [[ell (unit)|ell]], and [[yard]] were likewise shrunk, while [[rod (unit)|rod]]s and [[furlong]]s remained the same.<ref name="1977zupko">{{cite book | last = Zupko | first = Ronald Edward | author-link = Ronald Edward Zupko | title = British Weights and Measures: A History from Antiquity to the Seventeenth Century | publisher=University of Wisconsin Press | year = 1977 | isbn = 978-0-299-07340-4 | pages = 6, 10, 20 | url = https://books.google.com/books?id=pWUgAQAAIAAJ }}</ref> The ambiguity over the state of the [[mile]] was resolved by the 1593 [[Act against Converting of Great Houses into Several Tenements and for Restraint of Inmates and Inclosures in and near about the City of London and Westminster]], which codified the [[statute mile]] as comprising 5,280&nbsp;feet. The differences among the various physical standard yards around the world, revealed by increasingly powerful [[microscope]]s, eventually led to the 1959 adoption of the [[#International foot|international foot]] defined in terms of the meter.