Firmitatis Utilitatis Venustatis

The earliest surviving written work on the subject of architecture is De architectura, by the Roman architect Vitruvius in the early 1st century CE. According to Vitruvius, a good building should satisfy the three principles of firmitatis utilitatis venustatis, which translates roughly 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.

(--taken from Wikipedia)