 In the grammar of architecture, the word "petrification" is often used when discussing the development of sacred structures such as temples, mainly with reference to developments in the Greek world.During the Archaic and early Classical periods (about the 6th and early 5th centuries BC), the architectural forms of the earliest temples had solidified and the Doric emerged as the predominant element.A widely accepted theory in classical studies is that the earliest temple structures were of wood and the great forms, or elements of architectural style, were codified and rather permanent by the time we see the Archaic emergent and established.