Lester B. Holland, professor of Architecture at the University of Pennsylvania, addresses the puzzle of Doric entablature . The Greeks used this form continuously for a period of over four hundred years without showing the slightest variation in the arrangement of regulae, taenia, triglyphs, metopes, mutules, and corona, or even in the number and disposition of the guttae, and with practically no change in the relative proportions of these parts, is a fact unparalleled in architectural history. Holland suggests that this lack of variation in a situation where there is no structural need for the form to remain constant stems from its origin in the crenelation of defensive walls. This argument provides intriguing suggestions of the connection between the Mycenaean megaron and the classical temple, showing how architectural remains can illuminate larger cultural movements.