In Gaul, a unit of itinerant distance, which the Romans characterized as = 1500 passus, thus = 1½ mille passus, about 2.222 kilometers. The unit was officially adopted with this value by Rome for use in the Celtic areas of the European continent in the 3rd century. Also spelled leuga.


In England, a unit of itinerant distance often encountered in laws of the 13ᵗʰ and 14ᵗʰ centuries, sometimes = 2 miliare = 10,000 feet. De Morgan estimated it at 15,312 feet (see source 1 below).



The leuca of the antient English law writers is necessary to be determined before the rights given by many charters can be defined; but unfortunately the length of this measure is enveloped in utter confusion. The modern lawyers, we believe, evade the question by setting it down as a mile; thus the legal minimum distance between two markets, which was certainly seven leucæ, is now called seven miles.

This [Gaulish] leuca in all probability was brought by the Normans into England. It is true that the Saxon charters of Ingulphus describe distances in leucæ; but the genuineness of these charters is now considered more than questionable, and perhaps this very circumstance is a presumption against them. But the leuca soon began to vary in size. Ducange cites an old metrologist who speaks of two leucæ, the one legal, of 3000 paces, the other common, varying much in different countries.…The registers of Battle Abbey (Sir H. Ellis) and the 'Monasticon Anglicanum' (Ducange) describe the leuca as containing 12 quarantenæ, or furlongs. Now the furlong (forty-long) is always 40 perches, and the perch, though varying much, yet was settled very early at 16½ feet. This gives a modern statute mile and a half to the leuca; so that a certain set of old authorities countenance the notion that the leuca was in their time very little more than that of the Gauls.

The earlier statutes do not define the itinerary measures; confining themselves entirely to those by which land and goods were bought and sold. And the itinerary measures seem to have been on the increase, perhaps for the following reason:-The jurisdiction of towns, monasteries, &c., was usually defined as extending a leuca or a given number of leucæ in every direction from their precincts, so that it became the interest of these powerful bodies to make the leuca as long as possible.…Ingulphus perhaps lets us a little into the secret when, speaking of his own monastery, he says, “Prudentissimi metatores, contra malitiam emulorum nostrorum piissime providentes, potius plus quam minus ponere voluerunt.” The same Ingulphus informs us that in his time the usual league was of 2000 paces, or 1.835 modern English miles, if the Roman pace be meant: but he adds that the English, adopting a Norman word to their own measure, frequently spoke of leucæ when they meant miles. But it may be questioned whether the mile and the leuca ever became interchangeable words in writings or charters, at least in England: in several continental countries the term mile never became vernacular, and miliare is therefore translated by league.

There is sufficient evidence to show, that whatever the mile of a later date may have been, the leuca was generally two miles; though instances occur in which it is still described as 1500 paces.…

Bracton (Henry III.) and Fleta (Edward I.?) both assert (see the citations in Cowell, Comyns's 'Digest,' &c.) 6 1eagues and half a league and the third part of a half (or 6 2/3 leagues) as being the distance between two markets which do not injure each other: because 20 miles is a reasonable day's journey : now (both of them say) if the dieta, or day's work, be divided into three parts, the first is for going to the market, the second for business, and the third for returning. This appears to mean that no market should be established within a third of a day's journey of any one who is already within a third of a day's journey of the established market, so as to give him the option of going to either: that is, the two markets must be at least 2/3 of 20 miles apart, which being further described as 6 2/3 leagues, shows that the leuca is two miles. This quotation is important as establishing the meaning which the old law writers attached to the word.

It may then, we think, be confidently asserted, that the league, which began as a mile and a half (Roman), soon became lengthened, until it remained fixed at two of the miles of the day. It appears also that this length of two miles was a settled league at so early a period, that it is the measure of our oldest law writers, and of most of the oldest charters. It depends therefore upon the mile of the thirteenth and fourteenth centuries.…We shall finish this article by stating our conviction that the length of the league or leuca was, in the time of the old law writers, very near, one way or the other, to two modern statute miles and nine-tenthsof a mile; the old mile being to the modern statute mile in the proportion of 45 to 100.

A. De Morgan.
Penny Cyclopædia of the Society for the Diffusion of Useful Knowledge, vol. 13.
London: Charles Knight and Co., 1839.
Page 376.


Certa Mensura Cartuariensis

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