A Roman milestone (miliarium) was a stone column set beside a road, usually one Roman mile apart. Many named the emperor responsible and some gave a distance. Our map does not show milestones, because the dataset has none.
Key takeaways
- Roman milestones were stone columns beside the road, first set up on the Appian Way [1].
- Many recorded only the name of the reigning emperor, with no place names or distances [1].
- At the centre of Rome stood the Golden Milestone, which marked the presumed centre of the empire and has since been lost [1].
- Our data holds 14,769 road segments but no milestones, so none appear on the map.
How Roman milestones worked
A Roman milestone, or miliarium, was a column or post set beside a road to mark its miles. The name comes from the Latin for a mile, and the distance between markers followed the Roman mile, about 1,479 metres [2]. They were widely used by Roman road builders and were an important part of any road network [1].
The earliest Roman milestones appeared on the Appian Way [1]. They were first made of stone, shaped as obelisks or columns from granite, marble or whatever local stone was to hand, and in later centuries sometimes of concrete [1]. A stone would then be cut with a Roman numeral for the number of miles from a starting point [2].
What they actually said varied. Many Roman milestones record only the name of the reigning emperor, without any place name or distance [1]. That made them as much a notice of who had built or repaired the road as a distance marker. Gaius Gracchus, a tribune in 123 to 122 BC, is recorded as having provided public roads with milestones and mounting blocks for riders [3].
Distances in Rome were measured from a central point. At the heart of the city stood the Golden Milestone, which marked the presumed centre of the empire. It has since been lost [1]. The idea that every road started at one marker is part of the story behind all roads leading to Rome, though that saying is only half true.
To space the markers, Roman surveyors needed to measure long distances accurately. Odometers were used for measuring the spacing, most likely based on Greek technology [1].
An example from our data
Our map does not show milestones. The Itiner-e atlas that supplies our data traces roads as lines, with 14,769 segments in total, and it has no point layer for milestones, bridges or road stations. So you cannot tap a milestone on the map, and the map should not be read as saying where they stood.
What you can look at is the road that milestones began on. The Via Appia is 576 km in our data, with 16.1% of that length classed as certain and the rest conjectured. In this dataset the certainty classes come from Itiner-e's own method, not from a count of milestones. Our how to read the map section explains the classes.
Britain's roads such as the Fosse Way are drawn the same way, as lines only, with no milestone layer.
The thing people get wrong
People often picture every Roman milestone as a neat stone saying "XX miles to Rome". Some did give a distance, but many gave only the emperor's name [1]. A stone with no distance on it is not a mistake. Its job was to record who was responsible for the road.
A second misunderstanding is to treat milestones as proof that a road is exactly where the map draws it. A milestone is a clue to where a road ran, but the map's line comes from the Itiner-e method and is mostly conjectured, with only 2.7% of the network classed as certain.
Frequently asked questions
How far apart were Roman milestones?
They were set to mark Roman miles along a road, so roughly one Roman mile apart, though the evidence varies from road to road.
Are Roman milestones on the map?
No. Our dataset has 14,769 road segments and no milestones, so the map shows the roads only.
What did a Roman milestone say?
Many carried only the name of the ruling emperor. Some gave a distance in Roman miles.
Sources
- Milestone, Wikipedia.
- Roman mile, Wikipedia.
- Roman roads, Wikipedia.
- Every figure from our own map is worked out from the datasets on the data sources page (checked against Itiner-e version 2024 1.3).