Even though most ancient cultures produced only a few buildings as a representation of the high-quality architecture in terms of religious and political ideas, the Hellenistic idea in such cities like Pergamon or Alexandra built entire cities as total works of architecture. And the Roman Empire adopted that approach to urban architecture through hundreds of cities.
The Romans conquered and absorbed different cultures, so their architecture urbanization was also affected by those absorption like structured on arches and vaults and articulated with marble columns. Architecture and urbanism became a vehicle of governance.
The city of Rome, considered itself as caput mundi which means “head of the world” and it commanded an international empire. They used architecture as a symbol of power of the empire. They took their models from some other Hellenistic cities and thy added them to a new architectural repertoire. Also, their architects produced a new type of city, in which public spaces in front page. Architects used arches, vaults and the new technology of construction and they overcame the irregularity of terrain.
During the first two centuries of Rome, they inspired from Etruscan culture. Etruscan architects brought them the technology of vaults and arched gateways. Romans imitated the Etruscan temple for their major cult. The Roman temples repeated the Etruscan architectural design.
In 501 BCE, the Roman republic changed with monarchy. With that change they designed a new space for political issues which is called as Forum. Forum was not like the Agora in the Greek culture, it was tightly enclosed by large columns.
Romans learned the orthogonal urban design from Greek. The city itself like other civilizations built up a grid system. Roman planners built up the city a cross-axis streets if the topography allowed.
In Rome, public spaces were very significant. Roman cities like Pompeii always contained a forum, a temple and a basilica. Generally, the temple stood at one end of the oblong space and a basilica. With the help of the considerable geographic distance between temples, we can understand that Roman architects used standard models that based on a modular proportional system.
Like other civilizations Romans produced temples and tombs and addition to them they also produced a disproportionate number of secular monuments such as theaters and baths. Contrast to Greek theaters, Romans built freestanding monuments using arches and vaults. The early Roman theaters mostly had a temple. The first theater is an example to that temple with theater issue. Also, the scene building was stood opposite the temple with three levels of columns. Moreover, the Romans developed a new form of theater which is amphitheater. Amphitheater occurred by adding two theater edge to edge.
Roman baths or another word thermae were another public space that Romans gave attention. The rooms inside the thermae were equally grand and they reflected the Hellenistic prototypes. There were a spatial organization through that rooms such as dressing room that movement of people started and ending with round room. Also, hypocaust was an important structural element. Hypocaust went through under-floor and it was for heating the place with circulation of hot air.
Ancient Roman houses -were also called as domus- tightly organized around colonnaded courts. The street façade had shops to either side of the entry. Front doors of the domus open t atrium which served for extended family. The typical domus’ court served as the feminine zone of the household and It surrounded by columns in a peristyle It also included kitchens, triclinium dining rooms, baths and privies. Suburban villas emerged in the second century BCE. They had the courts of domus type with gardens and landscape vistas.Insula or multilevel apartment block developed spontaneously with the help of shops that below the houses.
Richard Ingersoll-Spiro Kostof, World Architecture: A Cross-Cultural History, p.148-163