After this development of the principles on which we have proceeded in our examination, it is necessary to add a few observations on the Roman mile, the standard of measurement used in compiling the Itineraries; because many difficulties in determining the stations arise from our uncertainty respecting its real length. It may indeed appear easy to ascertain this point, by a careful measurement of the space between two military columns, still existing on any known Roman road. But in Britain such an experiment has been hitherto impracticable; for the columns in our island have been so universally defaced or removed, that, far from two existing on the same road, only one has been found[687] whose original station is known with any degree of certainty. In France and Italy many of these columns still exist, and Danville has adduced three instances in Languedoc, in which the distances between them accurately measured amounted in one to 756, in another to 753, and in a third to 752 toises and two feet. The average 754 toises and two feet, seems to determine the length of the Roman mile with sufficient precision; and the result is confirmed by a comparison with the Roman foot, still preserved in the capitol; for the exact length of the miles between the military columns on the Appian way, in the neighbourhood of Rome, as measured by Bianchini, was 5010 of these Roman feet, which reduced to toises is 756 toises four feet and a half. From these results Danville estimates the Roman mile at 755 toises, or 1593 yards[688] English measure.
Unfortunately this mensuration does not lessen the difficulties of the English antiquary; for the distance between any two of our known stations, if measured by this standard, disagrees in almost every instance with the numbers of the Itineraries. Different conjectures have been advanced to solve this difficulty. One, supported by the respectable authority of Horsley, is, that the Romans measured only the horizontal distance, without regarding the inequalities of the surface; or that the space between station and station was ascertained from maps accurately constructed. This idea receives some support from a fact acknowledged by every British antiquary, namely, that the Itinerary miles bear a regular proportion to the English miles on plains, but fall short of them in hilly grounds. Another opinion is, that the Itinerary miles were not measured by an invariable standard, but in the distant provinces were derived from the common measures of the country. In support of this conjecture a supposed coincidence between the computed and measured miles, noticed by Horsley and others, has been adduced; but if this were the case, there would not be so exact a conformity between the miles of France and Italy as appears in the instance before mentioned.
To remove, however, as many causes of error as possible, considerable pains have been taken to correct the numbers, by a comparison of all the earliest and most authentic copies of the Itinerary. These are: The Itinerary of Talbot, published in Leland's works. That of Camden. Two copies by Harrison, published first in Hollingshed, and republished by Burton. That of Gale. That of Surita, who collated five copies, four of which he thus designates:—1. Bibliothecæ Regiæ ad D. Laurent. vetustisa. Codex Ovetensis Æra IƆƆCCCCXX descriptus. 2. Bibliothecæ Blandiniæ pervetustus codex a CCCC. circiter annis transcriptus. 3. Bibliothecæ Neapolitanorum Regum qui post cardinalis de Ursinis fuit anno M.CCCCXXVII. exscriptus. 4. Christophori Longolii exemplar ab H. Stephano. Parisiis editum, anno M.IƆXII.
As the Roman posts and roads were in a great degree connected with, or derived from, the British towns and trackways, we proceed to trace first the course of the British roads which still exist, and to specify the towns whose sites are known, premising that of the ninety-two capital towns of the Britons commemorated by historians, the names of only eighty-eight have been preserved.
The British ways were,—
1. The Watling Street, or Irish road, in two branches, northern and southern.
2. The Iknield Street, or road of the Iceni, the inhabitants of the eastern coast.
3. The Ryknield Street, leading through the country of the Upper Iceni or Coritani.
4. The Ermyn Street, leading from the coast of Sussex to the south-east part of Scotland.
5. The Akeman Street, or intermediate road between the Iknield and Ryknield Street.