The Antonine Itinerary

The Antonine Itinerary is the name given to a document which gives details of the Roman road network of Europe around the third century AD. It is a copy of an original Roman document, listing the villages, towns and cities along the main trunk routes. It gives us the Roman place-names (some still to be identified) and the roads between them. There is an added bonus in that distances are also quoted, in Roman miles. There is a section devoted to the British roads.

In this British section, there are fifteen ‘itineraries’, or routes. (They are numbered I to XV in modern editions – the original routes were not numbered). They all have a start and and an end, total distance, then the principal points in between, all with distances between noted in Roman miles. Some of these would have undoubtedly been the site of an official mansio, or inn, where Roman officials would have been able to have a comfortable bed for the night, and fresh horses would have been available for the next days’ travel. Some of the place-names in the list are easily identified, such as Londinio (London) but others are to this day are difficult to place.

The Itineraries that cover sections of road in the Hampshire area are:

  • Itinerary VII – Chichester to London, via Bitterne, Winchester and Silchester
  • Itinerary XII – Carmarthen to Wroxeter (though the part through Hampshire seems to be a clerical error
  • Itinerary XIII – Caerleon to Silchester
  • Itinerary XIV – Another route from Caerleon to Silchester
  • Itinerary XV – Silchester to Exeter

The Length of a Mile
The Antonine Itinerary has distances between towns in Roman miles. Each itinerary starts off with the initials ‘m.p.’ or milia passuum – thousand paces – the basis of the Roman mile. According to Margary, the Roman mile was measured as 1,000 paces of a runner’s stride of five feet. This makes a Roman mile about 1,680 yards, just shy of a standard British mile of 1,760 yards. A British mile is of course 1.609344 kilometers, and so a Roman mile works out as 1.536192 kilometers. The word mile is of course from the Latin milia meaning a thousand, or in the metric system, ‘mille’, so there is a possibility that this British measure derived from the Roman measure, although other countries including Norway and Sweden have similar words, though remained outside the Roman empire.

Estimates of the length of a Roman mile exist outside of Margary of course. Wikipedia currently estimates a Roman mile at 1,617 yards – this is 1.47858 kilometers , then on another page, there is another estimate of  1620 yards. Sir William Charles Smith estimated it to 4854 feet – 1618 yards in his monumentally titled A new classical dictionary of Greek and Roman biography, mythology, and geography partly based upon the Dictionary of Greek and Roman biography and mythology, of 1851.

[Edit: See my new post about John Michell and the Roman Mile]

Roman Numbering
The Roman numbering system was completely different to our arabic numbering system. Although the Romans counted in base 10, like us, the notation for the actual numbers used letters arranged in an easily understood system, like tally marks. One was I, two was II, and so on, until five, which was V. Six was VI, seven was VII until ten was reached, which was signified by X. Eleven was XI, twelve was XII until fifteen was reached, which was XV. This continued until 50 was reached, which was expressed as l. Other special notations included C for century and M for mille, or thousand. Five hundred was D, standing for ‘demi’ or half.

A subtlety of the system was the ability to put a smaller value letter before a larger value letter (normally the order is largest to smallest). It simply means take the smaller value away from the greater value. This allows nine to be expressed as IX (10 minus 1) instead of the slightly cumbersome VIIII. Similarly 99 can be expressed as IC and so on. Here are the first twenty numbers:

  1. I
  2. II
  3. III
  4. IV (sometimes IIII)
  5. V
  6. VI
  7. VII
  8. VIII
  9. IX (sometimes VIIII)
  10. X
  11. XI
  12. XII
  13. XIII
  14. XIV (sometimes XIIII)
  15. XV
  16. XVI
  17. XVII
  18. XVIII
  19. XIX (sometimes XVIIII)
  20. XX

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