Leonardo da Vinci – a basic
principle
1. The planning of temples depends upon symmetry: and the
method of this architects must diligently apprehend. It arises from
proportion (which in Greek is called analogia). Proportion consists
in taking a fixed module, in each case, both for the parts of a
building and for the whole, by which the method of symmetry is
put to practice. For without symmetry and proportion no temple
can have a regular plan; that is, it must have an exact proportion
worked out after the fashion of the members of a finely-shaped
human body.
from Vitruvius' De Architectura