HISTORY122 - Ancient Roman Roads

My last blog on the history of road signs introduced me to the awesome road system of the ancient Romans.  Right then, I knew that was my next blog subject.

 

After an introduction, that includes a short history of Rome’s growth, I will discuss the history of the Roman road system: Why the Roman Road System was so Important, Construction and Engineering, Infrastructure and Road Services, Vehicles and Transportation, Decline and Legacy, and Conclusions.  

As usual, I will list my principal sources at the end.

 

Introduction

The history of Roman roads began with the Roman Republic’s military expansion in the 4^th century BC and resulted in a vast, highly engineered network that was crucial to maintaining and administering the Roman Empire.

To put the history of Roman roads in perspective, here is a short summary of the growth of Rome.

Rome was founded around 753 BC as a small settlement, a monarchy.  In 509 BC., the monarchy was overthrown and the Roman Republic was established, led by two elected consuls and a powerful Senate.  In 27 BC, Rome transitioned to an Empire, ruled by emperors. 

Rome grew into a vast territory by military conquest, expanding across the Italian peninsula, the Mediterranean, and into Europe, North Africa, and parts of Asia.  Growth was driven by a desire for resources and power, fueled by a strong military, and supported by infrastructure, standardized currency, and the extension of citizenship to many conquered peoples.  The Empire's expansion peaked around AD 117, before eventually dividing and declining in the West, which fell in AD 476, while the East continued as the Byzantine Empire for another thousand years.

In 272 BC, the surrender of the Greek city of Tarentum signified the Republic of Rome's complete dominance over the Italian peninsula.  Dominating Italy allowed Rome to look beyond its borders, leading directly to the Punic Wars, a series of three conflicts fought between the Roman Republic and the Carthaginian Empire between 264 and 146 BC. The rivalry resulted in the complete destruction of Carthage and the Roman Republic’s establishment as the dominant power in the Mediterranean.  

 

The key expansion periods for the Western Roman Empire.

In 133 BC, internal crises triggered a century of political violence that would ultimately destroy the Roman Republic.  However, between 133 BC and AD 14, the Roman state dramatically expanded its territory, transforming from a dominant republic in the Mediterranean into a vast Empire encompassing most of Europe and North Africa.

The beginning of the Roman Empire is traditionally marked by the year 27 BC, when Augustus became the first emperor of Rome.  This event marked the end of the Roman Republic and ushered in a new era of autocracy, following a period of civil unrest and the assassination of Julius Caesar.  The death of Augustus and the succession of Tiberius in AD 14 proved the new imperial system was durable and not dependent on a single charismatic leader.  Tiberius’ reign was a period of relative peace and stability, which allowed the Empire to flourish. 

The year AD 117 marks the death of Emperor Trajan, under whose rule the Roman Empire reached its greatest territorial extent, following the conquest of Britain, Dacia, Arabia, Armenia, and Mesopotamia.  The Empire stretched from northern Britain to the Persian Gulf.  After Trajan's death, his successor, Hadrian, began a policy of consolidating and defending the existing borders rather than expanding further. 

The Romans built roads continually as a natural and integral part of their Empire's expansion and consolidation. The road network was a cornerstone of Roman power and a primary tool for establishing and maintaining control over conquered territories. 

Roman roads were of several kinds, ranging from small local roads to broad, long-distance highways built to connect cities, major towns, and military bases. These major roads were often stone-paved, cambered for drainage, and were flanked by footpaths, bridleways, and drainage ditches. They were laid along accurately surveyed courses, and some were cut through hills with tunnels or conducted over rivers and ravines on bridgework.  Sections could be supported over marshy ground on rafted or piled foundations.

At the peak of Rome's expansion, no fewer than 29 military highways radiated from the capital, and the Empire's 113 provinces were interconnected by 372 roads.  At its greatest extent, the system spanned over 250,000 miles, with more than 50,000 miles of stone-paved highway connecting provinces from Britain to Syria. 

Roman road network at the peak of the Empire’s expansion in AD 117.

 

Though adapting their road construction technique to materials locally available, the Roman engineers followed basically the same principles in building abroad as they had in Italy.

Why the Roman Road System was so Important

The network of public Roman roads greatly assisted the free movement of armies, people, and goods across the Empire.  Roads were also a very visible indicator of the power of Rome, and they indirectly helped unify what was a vast melting pot of cultures, races, and institutions.

Military Necessity: The primary purpose of the Roman road system was military logistics.  Roads enabled the swift movement of troops, supplies, and communications throughout conquered territories.  The roads allowed legions to move quickly to suppress revolts or defend against external threats, ensuring that the Roman military could out-pace and out-maneuver its enemies.  Fleet-footed legions could move as quickly as 20 miles a day to respond to outside threats and internal uprisings.   Even the most isolated parts of the Roman world could expect to be swiftly supplied or reinforced in the event of an emergency, lessening the need for large and costly garrison units at frontier outposts.  The construction of roads into new territories was also a powerful tool for demonstrating Roman control and making the Empire's authority felt across vast distances.  

Roman roads enabled the swift movement of Roman troops.

Communication: The roads enabled efficient long-distance communication through the imperial postal service.  Imperial couriers on horseback could travel up to 50 miles per day.  In emergencies, a relay of riders could cover significantly greater distances in a single day, ensuring that urgent messages and military orders reached their destination at astonishing speeds for the ancient world.

Trade and Commerce: Although not initially built for economic reasons, the roads soon became vital for transporting goods and connecting towns, stimulating economic development.  By providing stable, secure routes for merchants and goods, Roman roads fostered unprecedented levels of commerce.  Later, the swift movement of commodities such as grain, metals, olive oil, and wine fueled economic growth and integrated regional markets into the larger imperial economy.  The road network was a major driver of economic prosperity and promoted urban growth.  Cities and towns often emerged and flourished at strategic road junctions.

Cultural exchange: The Roman system of roads was a conduit for spreading Roman culture, language, and legal systems throughout the Empire.  It also facilitated the exchange of art, and ideas.

Religious Spread: The well-maintained and interconnected roads were instrumental in the spread of Christianity.  Early Christian missionaries and pilgrims, such as the Apostle Paul, could travel and spread their faith efficiently across a diverse audience.

Public Works and Propaganda: The impressive, long-lasting construction of the roads served as a powerful symbol of Roman engineering prowess and imperial prestige. Features like bridges, tunnels, and triumphant arches often marked the roads, displaying the power of Rome to its citizens and subjects alike. 

 

Construction and Engineering

Roads. Before the widespread adoption of paved roads, the Romans used leveled earth and gravel tracks, possibly influenced by Etruscan and Carthaginian techniques. 

Romans began to pave roads in 312 BC with the start of construction on the Appian Way as a supply route between republican Rome and its allies in Capua in southern Italy during the Second Samnite War.  As the Roman Republic expanded across Italy in the 3^rd and 2^nd centuries BC, it built more great roads radiating from the capital.  These projects marked the beginning of the Roman road system.

Roman roads were celebrated for their durability and efficiency, a testament to superior engineering that adapted to local terrain and available materials.  The width of Roman roads varied, but standard two-way roads were around 4.2 meters (13.8 feet), allowing two carts to pass, while smaller public roads were often about 2.4 meters (8 feet) wide.  Major roads were wider, with some reaching 12 meters (39 feet).

Major roads typically featured a multi-layered construction for stability and drainage.   

1.     Crews began by digging shallow, three-foot trenches to establish a solid base, and erecting small retaining walls along either side of the route.

2.       The foundation was laid of rubble, compacted sand, or dry earth.

3.       A layer of slabs of stone was added above the foundation.

4.       A layer of pebbles and gravel in cement mortar was added over the stone slabs.

5.       The surface layer consisted of tightly fitted, smooth polygonal paving stones.

 

Major roads typically featured a multi-layered construction for stability and drainage.

Cement was used in Roman roads as a binding agent in all layers, and in many cases, the paving stones were set in cement for the final surface layer to create a smooth, low-maintenance road.  Roman “cement” was a mixture of hydrated lime and a volcanic ash called pozzolana.

Roads were built with a slight curve, or "camber," in the middle to allow rainwater to drain into ditches on either side.  In marshy areas, roads were raised on embankments. 

Roman engineers prioritized straight routes, using a surveying tool called a groma to lay out direct paths.  A groma consisted of a vertical pole with a wooden cross on top, from which four plumb lines hung.  By sighting along these plumb lines, surveyors could mark straight lines and intersect them at 90 degrees, ensuring that alignments remained true over distance.  

Roman surveyor using a groma to lay out direct paths.  

The Romans also constructed bridges and tunnels to maintain straightness over difficult terrain like rivers, ravines, and hills or small mountains. 

Bridges. Roman bridges were some of the first large and lasting bridges created.  A bridge could be of wood, stone, or both.  Wooden bridges were constructed on pilings sunk into a river, or on stone piers.  Stone arch bridges were used on larger or more permanent crossings.  Most bridges also used concrete, which the Romans were the first to use for bridges.  Roman engineers built over 900 bridges on their roads, with most surviving today and some still in use

The Romans perfected the use of arches, which allowed them to build strong, rigid bridges capable of withstanding immense weight by directing forces down to the foundations.  They used volcanic ash mixed with lime and gypsum to create hydraulic concrete that could set underwater, a revolutionary development for building bridge piers.  To build piers in rivers, they employed cofferdams, temporary watertight enclosures, to create a dry work environment.  They standardized bridge components, which made construction faster and allowed for easier repairs, and helped spread bridge-building expertise throughout the Empire.  Roman engineers carefully selected bridge locations to minimize construction challenges by working with the natural landscape.  They used iron clamps to hold stones together, and in later periods, began using materials like ashlar (masonry made of large square-cut stones, typically used as a facing on walls of brick or stone), bricks, and concrete for bridge footings and water channels. 

Causeways were built over marshy ground. The road was first marked out with pilings.  Between them were sunk large quantities of stone so as to raise the causeway to more than 5 feet (1.5 meters) above the marsh. In the provinces, the Romans often did not bother with a stone causeway but used log roads.

 

The Puente Romano, over the Guadiana River at Mérida in southwest Spain, is the longest Roman bridge still in use at 2,365 feet.

Tunnels.  Roman roadway tunnels were constructed to penetrate hills, allowing for direct routes for military and civilian travel.  Romans used counter-excavation, where teams tunneled from both ends of the hill to meet in the middle, a feat requiring precise geometric planning.  Vertical shafts were sometimes dug to check progress and aid excavation.  Tunnels were often carved out of volcanic rock. 

Notable examples include the 1 km long Grotta di Cocceio tunnel, in southern Italy, and the Crypta Neapolitana tunnel, over 700 meters long, near Naples, both built in the 1^st century BC, showcasing the Romans' advanced engineering and construction techniques.

The Grotta di Cocceio, the first great road tunnel in the world, built by the Romans in 36 BC.

The Roman military built and maintained the Roman road system, including bridges and tunnels, using legions of soldiers for the labor and engineers for the design.  Prisoners, criminals, slaves, and paid labor were also sometimes employed in the construction.  Building and maintaining roads, bridges, and tunnels was considered a crucial military task, with soldiers performing construction work, especially between campaigns.  This kept soldiers busy, in shape, and prepared for military movement.

 

Infrastructure and Road Services

Administrative Structure. The administration of Roman roads involved state-level planning and funding, with central officials overseeing construction and maintenance.  Construction and upkeep were financed by a combination of taxes, tolls, and patronage from emperors or private citizens.  Major road projects were planned from Rome itself as a matter of strategic importance.

Milestones. To help travelers navigate on Roman roads, the Romans installed milestones - cylindrical stone columns engraved with information such as the distance from Rome, the distance to the next major city, and the name of the reigning emperor.

The columns were made of granite, marble, or whatever local stone was available.  Each measured between 6.6 to 13.1 feet high, with a diameter of 19.5 to 31.5 inches, and were placed at approximately one-mile intervals.  Based on the entire road network's length, historians estimate that hundreds of thousands of milestones existed throughout the Roman Empire. 

Example of Roman milestone, engraved in Latin.

Traveler Services. For official travel, the Roman government maintained horse-changing stations and way stations on Roman roads.  A system of private inns and hostels also existed for other travelers.

The horse changing stations were located every 10 miles along most routes. These simple posthouses consisted of stables where government travelers could trade their winded horse or donkey for a fresh mount. Switching horses was especially important for imperial couriers, who were tasked with carrying communications and tax revenues around the Empire at breakneck speed.  By stopping off at multiple posthouses, couriers could move as far as 50 miles in a single day.

Along with the more common horse changing stations, travelers could also expect to encounter both government and private waystations, roughly every 20 miles.  Each way station offered basic lodgings for people and their animals as well as a place to eat, bathe, and repair wagons.

Remains of a cozy kitchen which fed travelers on the Roman road at the villa of Bad Neuenahe-Ahrweile , Germany in the 3^rd century AD.

Security Patrols: To combat thieves and highwaymen, most Roman roads were patrolled by special detachments of imperial army troops.  These soldiers manned police posts and watchtowers in both high traffic and remote areas to help guide vulnerable travelers, relay messages, and keep an eye out for runaway slaves.  They also doubled as toll collectors.  Like modern highways, Roman roads were not always free of charge, and troops were often waiting to levy fees or taxes on goods whenever the route reached a bridge, mountain pass, or provincial border.

Postal Service. Two postal services were available under the Empire, one public and one private. The public postal service, establish by Emperor Augustus, carried the mail of officials by relay throughout the Roman road system. The vehicle for carrying mail was a two-wheeled cart (pulled by one or two horses) with a box, but for special delivery, a horse and rider was faster. The postal service was a somewhat dangerous occupation, as postmen were a target for bandits and enemies of Rome.  Private mail of the well-to-do was carried by an organization of slaves, and available for a price.

Mapping and Control: The detailed road itineraries and navigation milestones were essential for surveying and controlling the vast Empire. This allowed Rome to maintain a comprehensive grasp of its territories, demonstrating its authority. 

Much of what historians know about Rome’s system of roads comes from a single artifact.  Named for its medieval owner, Konrad Peutinger, the Peutinger M is a 13^th century copy of an actual Roman map created sometime around the 4^th century AD.  This atlas was drawn on a 22-foot-long collection of parchment and shows the entire Roman world in full color along with several thousand place names.  Cities are illustrated with sketches of small houses or medallions, but the map also includes the locations of lighthouses, bridges, inns, tunnels, and - most importantly - the Roman highway system.  All the major Roman roads are listed, and the map even gives the distances between various cities and landmarks.  The Peutinger map has proven indispensable to scholars studying the Roman transit system.

Peutinger Map (section of a modern facsimile), top to bottom: Dalmatian coast, Adriatic Sea, southern Italy, Sicily, and the African Mediterranean coast.
 

Vehicles and Transportation

Vehicles that traveled on Roman roads included chariots, carts, and wagons for both civilian and military purposes.

Passenger and Public Vehicles: Included a light, fast two-wheeled chariot often used by messengers; a two-wheeled, comfortable, and convertible carriage for two people, often pulled by two mules or horses; a two-wheeled carriage with a wooden roof, more comfortable than other cars, used by wealthy Romans; and a four-wheeled carriage, equivalent to a bus or stagecoach, which could carry multiple passengers and was drawn by up to four horses or mules. 

Recreation of a four-wheeled multiple-passenger Roman traveling carriage.

Goods and Military Vehicles: Included a heavy cart with two or four solid wooden wheels, often pulled by oxen, used for transporting goods like farm produce; a large cart used for transporting families or as a war wagon; and a heavy, ox-drawn cart used as a military supply van. 

 

Decline and Legacy

The Roman system of roads declined with the fall of the Western Roman Empire in AD 476, leading to a loss of maintenance, but its legacy endured through medieval use, its adaptation into modern roads, and its lasting influence on European trade and economic development.  

Decline. After the Western Roman Empire collapsed, the state could no longer fund maintenance, leading to roads falling into disrepair and many sections becoming impassable.  Without central oversight, many roads were abandoned, and their stones were sometimes taken for other building projects.  Periods of political and economic decline, even before the final collapse, caused sections of the road network to fall into disrepair, demonstrating that even advanced engineering requires upkeep. 

Legacy. Many Roman roads survived the fall of the Empire and became the main routes for trade and travel in the Middle Ages and beyond, such as in Anglo-Saxon Britain.  Many Roman roads were used as major thoroughfares until only recently, and some still carry car, bike and foot traffic.  Some Roman roads were incorporated into modern road networks, with modern highways sometimes built directly on top of the ancient ones, particularly in countries like the UK.  Rome’s enduring engineering legacy can also be seen in the dozens of ancient bridges and tunnels still in use today.

Research shows a lasting connection between the routes of Roman roads and modern economic activity, indicating that the infrastructure's impact on trade and wealth distribution has persisted over centuries.  Roman road-building techniques also influenced later engineers. The network remains a testament to Roman engineering, administration, and power, which facilitated trade, cultural exchange, and the movement of people across a vast Empire. 

 

Conclusions

The Romans built their amazing system of roads, as they expanded their geographical dominance, from 312 BC to AD 117, a period of 429 years.  At its peak, the Empire stretched from northern Britain to the Persian Gulf, an air-travel distance today of 3,145 miles.  There are over 50 modern countries that have territory that was once part of the Roman Empire, spanning Europe, North Africa, and the Middle East

 

While not a direct quote about the roads themselves, the famous scene in Monty Python’s movie, Life of Brian, is often referenced when discussing Roman contributions:

 

 

"All right... all right... but apart from the sanitation, the medicine, education, wine, public order, irrigation, roads, a fresh water system, and public health... what have the Romans ever done for us?"

 

 

Sources

My principal sources include: “Roman Roads,” Wikipedia.com; “8 Ways Roads Helped Rome Rule the Ancient World,” history.com; “Roman Road System,” Britannica.com; plus, numerous other online sources, including answers to many queries using Google in AI Mode.