ABSTRACT
William Penn developed the plan of what is now known as center-city Philadelphia in the middle of the seventeenth century. Penn’s plan for Philadelphia, an alloy of Quaker Utopianism and colonial real-estate speculation, is distinguished not only for its influence as a prototype in the founding of subsequent American cities, but for the ways in which its basic outlines have continued to endure in the form of the city’s historical center. Although not unique among North American cities for having been established with a deliberate plan, Philadelphia’s evolution over the past three centuries presents an singularly important case through which to examine the interplay between the concepts embodied in an originating plan, the material characteristics of the plan itself, and the historical circumstances that transform, usurp or supersede that plan.
