According to some accounts, the wealth of the ancient Roman empire was reflected in the very fabric of the city - with buildings of sparkling white marble at its centre. Even the founder of the Roman empire, Emperor Augustus claimed that he had 'found Rome a city of bricks and left it a city of marble'. But new research by historians at the University of California Los Angeles has now cast doubt on this boast. Scroll down to explore ancient Rome in 3D . This reconstruction by historians at the University of California shows how Rome would have looked under the rule of Augustus and reveals that many of the buildings were made from brick (shown in grey) while only a few temples were constructed from marble (pink) Using architectural computer modelling software they have been able to reconstruct the entire city to reveal how it would have looked during the rule of Augustus between 44BC and 14AD. The Pantheon, Trajan's Market and the Colosseum have remained standing for nearly 2,000 years. Scientists claim to have found a 'secret' ingredient in Roman concrete that helped it endure the elements. Using X ray beams at the Advanced Light Source (ALS), researchers were able to study a reproduction of Roman volcanic ash-lime mortar. In the concrete walls of Trajan's Markets, constructed around 110 CE, this mortar binds cobble-sized fragments of tuff and brick. Scientists looked at the mineralogical changes that took place in the curing of the mortar over a period of 180 days and compared the results to 1,900 year old samples of the original. The team discovered that the volcanic ash creates a crystal structure that prevents tiny cracks from spreading. They also found that the use of strätlingite crystals in the material showed no corrosion, with their smooth surface suggesting stability. They found that in fact only a small proportion of the buildings in Rome at the time were converted from brick into marble. Indeed, the few buildings that were built from marble were hidden from view within the city landscape, meaning many historical discriptions of the city's beauty were perhaps exaggerated. Their discovery suggests that the claim attributed to Augustus may have been more of a metaphor than a literal boast. Dr Diana Favro, who led the work, said: 'Many scholars have looked at Augustus’ claim from a political standpoint, as a metaphor for him transforming a republic into an empire. 'I wanted to see if Rome literally transformed under his rule. Given the literary descriptions and artwork, I thought these glittering marble temples on high would be very visible, but they were not.' Dr Favro used information from archaeological and historical records to produce the computer model that can show how the city evolved during Emperor Augustus' rule. Buildings constructed from marble were shaded with pink while those that were made from brick were shaded brown. Those under construction were yellow. When the researchers examined the model, they found just a few buildings were clad with marble, including the Temple of Venus and the Basilica Julia. Dr Favro found that when viewed from the street level, however, these buildings were not widely visible. Shortly before Augustus came to power, the Carrara marble quarries on the northwest coast of Italy were opened, and this was thought to have made marble a popular building material. Augustus commissioned several large marble structures, some of which took 40 years to complete. As a result, massive marble blocks were constantly being moved through the city, causing congestion in the streets. Marble-paved public spaces, which used to only be found in sacred temples and houses of the elite, were also added throughout the city. The 3D model (above) allows researchers to explore the city down to the street level and see how it changed between 44BC and 14AD . The Basilica Julia in the Roman Forum was one of the few buildings to be constructed from marble in Rome under Emperor Augustus . Dr Favro said this may be why Rome earned its reputation as a city of marble. She said: 'Because they saw construction taking place constantly, I believe people really did think that Rome had been transformed into marble. 'But in reality, the city did not greatly transform.' Many artworks, like the painting above, and historical accounts depict Rome under Augustus as being dominated by marble buildings .
Emperor Augustus boasted about how his rule left Rome 'a city of marble' while historical accounts said it glittered . Historians at the University of California Los Angeles have reconstructed ancient Rome using architectural software . They found that most of the buildings were built mainly from brick and only a few temples were made from marble . Those that were made from marble would have been difficult to see from many parts of the city, say the researchers .