Geometry is concerned with spatial relationships - that is, how one object relates to another in an open space. Before it was stratified and transformed between the 7th and 4th centuries BC, the system used was very much one of trial-and-error. The ancient Greeks applied 'axioms', or basic starting points and premises, to its study and in doing so created a much more logical framework within which to expand their theories. Men like Pythagoras created watertight rules that are still used today, yet the study of geometry as we know it today was mastered, or at least codified, by Euclid of Alexandria. He wrote the text 'Elements' in the 3rd century BC; it became the seminal geometry textbook until the early 20th century.
