The primary materials of the Romans was tile, marble, and even a type of concrete engineered and perfected by the Romans. Columns and arches are the most well known of Roman Architecture, but what is not as well known is the level of structural integrity of their creations. Massive trusses were used to hold up tons of stone for roofs. They also loved using phi and golden ratios to make their creations of natural/ earthly proportion. The architecture had a lot of spiritual representation within it. The different symbols and artwork within the architecture was created to represent aspects of divinity, along with events of astronomical importance being represented.