The earliest surviving written work on the subject of architecture is De architectura, by the Roman architect Vitruvius from the early 1st century CE. By Vitruvius, a good building should satisfy the three principles of firmitas, utilitas, venustas, which translate as:
§ Durability – it should stand up robustly and remain in good condition.
§ Utility – it should be useful and function well for the people using it
§ Beauty – it should delight people and raise their spirits.
According to Vitruvius, the architect should strive to fulfill each of these three attributes as well as possible. Leone Battista Alberti, who elaborates on the ideas of Vitruvius in his treatise, De Re Aedificatoria, saw beauty primarily as a matter of proportion, although ornament also played a part. For Alberti, the rules of proportion were those that governed the idealised human figure, the Golden mean. The most important aspect of beauty was therefore an inherent part of an object, rather than something applied superficially; and was based on universal, recognisable truths. The notion of style in the arts was not developed until the 16th century, with the writing ofVasari. The treatises, by the 18th century, had been translated into Italian, French, Spanish and English.