Romans are famous for their advanced engineering accomplishments,
although some of their own inventions were improvements on older
ideas, concepts and inventions. Technology for bringing running water
into cities was developed in the east, but transformed by the Romans
into a technology inconceivable in Greece. The architecture used in
Rome was strongly influenced by Greek and Etruscan sources.
Roads were common at that time, but the Romans improved their design
and perfected the construction to the extent that many of their roads
are still in use today. Their accomplishments surpassed most other
civilizations of their time, and after their time, and many of their
structures have withstood the test of time to inspire others,
especially during the Renaissance. Moreover, their contributions were
described in some detail by authors such as Vitruvius,
Pliny the Elder, so there is a printed record of their many inventions
8 Military engineering
9 Power technology
10 See also
13 Further reading
Main article: Roman aqueduct
Aqueduct of Segovia, Spain.
1,000 cubic metres (260,000 US gal) of water were brought
Rome by 14 different aqueducts each day. Per capita water usage
Rome matched that of modern-day cities like New York City
or modern Rome. Most water was for public use, such as baths and
De aquaeductu is the definitive two volume treatise on 1st
century aqueducts of Rome, written by Frontinus.
The aqueducts could stretch from 10–100 km (10–60 mi)
long, and typically descended from an elevation of 300 m
(1,000 ft) above sea level at the source, to 100 m
(330 ft) when they reached the reservoirs around the city. Roman
engineers used inverted siphons to move water across a valley if they
judged it impractical to build a raised aqueduct. The Roman legions
were largely responsible for building the aqueducts. Maintenance was
often done by slaves.
The Romans were among the first civilizations to harness the power of
water. They built some of the first watermills outside of Greece for
grinding flour and spread the technology for constructing watermills
throughout the Mediterranean region. A famous example occurs at
Barbegal in southern France, where no fewer than 16 overshot mills
built into the side of a hill were worked by a single aqueduct, the
outlet from one feeding the mill below in a cascade.
They were also skilled in mining, building aqueducts needed to supply
equipment used in extracting metal ores, e.g. hydraulic mining, and
the building of reservoirs to hold the water needed at the minehead.
It is known that they were also capable of building and operating
mining equipment such as crushing mills and dewatering machines. Large
diameter vertical wheels of Roman vintage, for raising water, have
been excavated from the Rio Tinto mines in Southwestern Spain. They
were closely involved in exploiting gold resources such as those at
Dolaucothi in south west
Wales and in north-west Spain, a country
where gold mining developed on a very large scale in the early part of
the first century AD, such as at Las Medulas.
Alcántara Bridge, Spain
Main article: Roman bridge
Roman bridges were among the first large and lasting bridges ever
built. They were built with stone, employing the arch as basic
structure. Most utilized concrete as well. Built in 142 BC, the Pons
Aemilius, later named Ponte Rotto (broken bridge) is the oldest Roman
stone bridge in Rome, Italy.
Roman bridge was
Trajan's bridge over the lower Danube,
constructed by Apollodorus of Damascus, which remained for over a
millennium; the longest bridge to have been built both in terms of
overall and span length. They were normally at least 18 meters
above the body of water.
An example of temporary military bridge construction is the two
Caesar's Rhine bridges.
The Romans built many dams for water collection, such as the Subiaco
dams, two of which fed Anio Novus, the largest aqueduct supplying
Rome. One of the Subiaco dams was reputedly the highest ever found or
inferred. They built 72 dams in Spain, such as those at Mérida, and
many more are known across the empire. At one site, Montefurado in
Galicia, they appear to have built a dam across the river Sil to
expose alluvial gold deposits in the bed of the river. The site is
near the spectacular Roman gold mine of Las Medulas.
Several earthen dams are known from Britain, including a
well-preserved example from Roman Lanchester, Longovicium, where it
may have been used in industrial-scale smithing or smelting, judging
by the piles of slag found at this site in northern England. Tanks for
holding water are also common along aqueduct systems, and numerous
examples are known from just one site, the gold mines at
Masonry dams were common in North Africa for providing a
reliable water supply from the wadis behind many settlements.
Colosseum in Rome.
Main article: Roman architecture
The buildings and architecture of Ancient
Rome were impressive even by
modern standards. The Circus Maximus, for example, was large enough to
be used as a stadium. The
Colosseum also provides an example of Roman
architecture at its finest. One of many stadiums built by the Romans,
Colosseum exhibits the arches and curves commonly associated with
The Pantheon in
Rome still stands a monument and tomb, and the Baths
of Diocletian and the
Baths of Caracalla
Baths of Caracalla are remarkable for their
state of preservation, the former still possessing intact domes. Such
massive public buildings were copied in numerous provincial capitals
and towns across the empire, and the general principles behind their
design and construction are described by
Vitruvius writing at the turn
of millennium in his monumental work De architectura.
The technology developed for the baths was especially impressive,
especially the widespread use of the hypocaust for one of the first
types of central heating developed anywhere. That invention was used
not just in the large public buildings, but spread to domestic
buildings such as the many villas which were built across the Empire.
The most common materials used were brick, stone or masonry, cement,
concrete and marble.
Brick came in many different shapes. Curved
bricks were used to build columns, and triangular bricks were used to
Marble was mainly a decorative material.
Augustus Caesar once boasted
that he had turned
Rome from a city of bricks to a city of marble. The
Romans had originally brought marble over from Greece, but later found
their own quarries in northern Italy.
Cement was made of hydrated lime (calcium oxide) mixed with sand and
water. The Romans discovered that substituting or supplementing the
sand with a pozzolanic additive, such as volcanic ash, would produce a
very hard cement, known as hydraulic mortar or hydraulic cement. They
used it widely in structures such as buildings, public baths and
aqueducts, ensuring their survival into the modern era.
Diagram of Roman road construction 
Main article: Roman roads
Roman roads were constructed to be immune to floods and other
environmental hazards. Some roads built by the Romans are still in use
There were several variations on a standard Roman road. Most of the
higher quality roads were composed of five layers. The bottom layer,
called pavimentum, was one inch thick and made of mortar. Above this
were four strata of masonry. The layer directly above the pavimentum
was called the statumen. It was one foot thick, and was made of stones
bound together by cement or clay.
Above that, there were the rudens, which were made of ten inches of
rammed concrete. The next layer, the nucleus, was made of twelve to
eighteen inches of successively laid and rolled layers of concrete.
Summa crusta of silex or lava polygonal slabs, one to three feet in
diameter and eight to twelve inches thick, were laid on top of the
rudens. The final upper surface was made of concrete or well smoothed
and fitted flint.
Generally, when a road encountered an obstacle, the Romans preferred
to engineer a solution to the obstacle rather than redirecting the
road around it: Bridges were constructed over all sizes of waterway;
marshy ground was handled by the construction of raised causeways with
firm foundations; hills and outcroppings were frequently cut or
tunneled through rather than avoided (the tunnels were made with
square hard rock block).
Drainage wheel from Rio Tinto mines.
The Romans were the first to exploit mineral deposits using advanced
technology, especially the use of aqueducts to bring water from great
distances to help operations at the pithead. Their technology is most
visible at sites in Britain such as
Dolaucothi where they exploited
gold deposits with at least 5 long aqueducts tapping adjacent rivers
and streams. They used the water to prospect for ore by unleashing a
wave of water from a tank to scour away the soil and so reveal the
bedrock with any veins exposed to sight. They used the same method
(known as hushing) to remove waste rock, and then to quench hot rocks
weakened by fire-setting.
Such methods could be very effective in opencast mining, but
fire-setting was very dangerous when used in underground workings.
They were made redundant with the introduction of explosives, although
hydraulic mining is still used on alluvial tin ores. They were also
used to produce a controlled supply to wash the crushed ore. It is
highly likely that they also developed water-powered stamp mills to
crush hard ore, which could be washed to collect the heavy gold dust.
At alluvial mines, they applied their hydraulic mining methods on a
vast scale, such as
Las Medulas in north-west Spain. Traces of tanks
and aqueducts can be found at many other early Roman mines. The
methods are described in great detail by
Pliny the Elder
Pliny the Elder in his
He also described deep mining underground, and mentions the need to
dewater the workings using reverse overshot water-wheels, and actual
examples have been found in many Roman mines exposed during later
mining attempts. The copper mines at Rio Tinto were one source of such
artifacts, where a set of 16 was found in the 1920s. They also used
Archimedean screws to remove water in a similar way.
Main article: Roman military engineering
Engineering was also institutionally ingrained in the Roman military,
who constructed forts, camps, bridges, roads, ramps, palisades, and
siege equipment amongst others. One of the most notable examples of
military bridge-building in the
Roman Empire was Julius Caesar's
bridge over the Rhine River. This bridge was completed in only ten
days by a dedicated team of engineers. Their exploits in the Dacian
Trajan in the early 2nd century AD are recorded on Trajan's
column in Rome.
The army was also closely involved in gold mining and probably built
the extensive complex of leats and cisterns at the Roman gold mine of
Wales shortly after conquest of the region in 75 AD.
Mills below aqueduct
Water wheel technology was developed to a high level during the Roman
period, a fact attested both by
Vitruvius (in De Architectura) and by
Pliny the Elder
Pliny the Elder (in Naturalis Historia). The largest complex of water
wheels existed at
Barbegal near Arles, where the site was fed by a
channel from the main aqueduct feeding the town. It is estimated that
the site comprised 16 separate overshot water wheels arranged in two
parallel lines down the hillside. The outflow from one wheel became
the input to the next one down in the sequence.
Twelve kilometers north of Arles, at Barbegal, near Fontvieille, where
the aqueduct arrived at a steep hill, the aqueduct fed a series of
parallel water wheels to power a flourmill. There are two aqueducts
which join just north of the mill complex, and a sluice which enabled
the operators to control the water supply to the complex. There are
substantial masonry remains of the water channels and foundations of
the individual mills, together with a staircase rising up the hill
upon which the mills are built. The mills apparently operated from the
end of the 1st century until about the end of the 3rd century. The
capacity of the mills has been estimated at 4.5 tons of flour per day,
sufficient to supply enough bread for the 12,500 inhabitants occupying
the town of Arelate at that time.
Scheme of the water-driven Roman sawmill at Hierapolis, Asia Minor.
Hierapolis sawmill was a Roman water-powered stone saw mill at
Asia Minor (modern-day Turkey). Dating to the second half
of the 3rd century AD, the sawmill is the earliest known machine to
combine a crank with a connecting rod.
The watermill is shown on a raised relief on the sarcophagus of Marcus
Aurelius Ammianos, a local miller. A waterwheel fed by a mill race is
shown powering two frame saws via a gear train cutting rectangular
Further crank and connecting rod mechanisms, without gear train, are
archaeologically attested for the 6th century AD water-powered stone
sawmills at Gerasa, Jordan, and Ephesus, Turkey. Literary
references to water-powered marble saws in Trier, now Germany, can be
found in Ausonius' late 4th century AD poem Mosella. They attest a
diversified use of water-power in many parts of the Roman Empire.
A complex of mills also existed on the
Rome fed by the
Aqua Traiana. The
Aurelian Walls were carried up the hill apparently
to include the water mills used to grind grain towards providing bread
flour for the city. The mill was thus probably built at the same time
as or before the walls were built by the emperor
270-275 AD). The mills were supplied from an aqueduct, where it
plunged down a steep hill.
The site thus resembles Barbegal, although excavations in the late
1990s suggest that they may have been undershot rather than overshot
in design. The mills were in use in 537 AD when the
the city cut off their water supply. However they were subsequently
restored and may have remained in operation until at least the time of
Pope Gregory IV
Pope Gregory IV (827-44).
Many other sites are reported from across the Roman Empire, although
many remain unexcavated.
List of Roman watermills
Pliny the Elder
^ Vinati, Simona and Piaggi, Marco de. “Roman Aqueducts, Aqueducts
in Rome.” Rome.info. Web. 5/1/2012
^ Duruy, Victor, and J. P. Mahaffy. History of
Rome and the Roman
People: From Its Origin to the Establishment of the Christian Empire.
London: K. Paul, Trench & Co, 1883. Page 17
^ Ville d'Histoire et de Patrimonie
^ La meunerie de Barbegal
^ Ritti, Grewe & Kessener 2007, p. 140
^ Ritti, Grewe & Kessener 2007, p. 161
^ Ritti, Grewe & Kessener 2007, pp. 139–141
^ Ritti, Grewe & Kessener 2007, pp. 149–153
^ Wilson 2002, p. 16
^ Örjan Wikander, 'Water-mills in Ancient Rome' Opuscula Romana XII
^ Örjan Wikander, 'Water-mills in Ancient Rome' Opuscula Romana XII
Davies, Oliver (1935). Roman Mines in Europe. Oxford.
Healy, A.F. (1999).
Pliny the Elder
Pliny the Elder on Science and Technology. Oxford:
Hodge, T. (2001).
Roman aqueducts and Water supply (2nd ed.).
Ritti, Tullia; Grewe, Klaus; Kessener, Paul (2007), "A
Relief of a
Water-powered Stone Saw Mill on a
Hierapolis and its
Implications", Journal of Roman Archaeology, 20: 138–163
Smith, Norman (1972). A History of Dams. Citadel Press.
Library resources about
Resources in your library
Resources in other libraries
Cuomo, Serafina. 2008. "Ancient written sources for engineering and
technology." In The Oxford handbook of engineering and technology in
the classical world. Edited by John P. Oleson, 15–34. New York:
Oxford Univ. Press.
Greene, Kevin. 2003. "Archaeology and technology." In A companion to
archaeology. Edited by John L. Bintliff, 155–173. Oxford: Blackwell.
Humphrey, John W. 2006. Ancient technology. Westport, CT: Greenwood.
McNeil, Ian, ed. 1990. An encyclopedia of the history of technology.
Oleson, John P., ed. 2008. The Oxford handbook of engineering and
technology in the classical world. New York: Oxford Univ. Press.
Rihll, Tracey E. 2013. Technology and society in the ancient Greek and
Roman worlds. Washington, DC: American Historical Society.
White, Kenneth D. 1984. Greek and Roman technology. Ithaca, NY:
Cornell Univ. Press.
^ Simona Vinati and Marco de Piaggi, “Roman aqueducts, Aqueducts in
Rome”, (Rome.info), Accessed