Philadelphia’s past and future always collided at the intersection of Broad and Market Streets. From the conception of Center Square in the 1680s to the laying of the corner stone for City Hall in 1874 it was a tentative, slow-motion collision. After that, things sped up quite a bit. By the end of the 19th-century, Broad and Market Streets had become the official center of Center City.

“It is the only place where a building of suitable dignity can stand to display its parts in all the beauty of their architectural effect,” speechified Benjamin Harris Brewster at the July 4th corner stone laying ceremony. City Hall “will adorn…the highways at whose intersection it is placed, and it will give an air of majesty and grandeur to those long and broad avenues. It…stands out in bold and high relief, commanding admiration. It is placed, as other and great structures are, as the center of human concourse from which all things radiate and to which all things converge. It is surrounded by a grand avenue 135 feet wide, on the southern and eastern and western fronts, and 205 feet wide on the northern front.”

After nearly two centuries, the Philadelphia envisioned by William Penn and his surveyor, Thomas Holme was finally coming together. Here was the city that “will never be burnt, and always be wholesome,” declared Penn, who insisted avoiding a re-creation of the London he had left behind. That city had been poised for conflagration, its wooden “rickety, slapdash buildings” leaning “against one another like drunks clutching each other for support,” writes Edward Dolnick, “an endless labyrinth of shops, tenements, and taverns with barely a gap to stop the flames.” London’s four-day fire of September 1666 left 100,000 of its citizens homeless, stunned amidst smoldering ruins.

Nothing like this would ever happen in Philadelphia, pledged Penn, who turned to the old Renaissance masters for fresh design ideas—ideas potent enough to eventually, centuries later, come to fruition in the center of Philadelphia.

“There are another Kind of public ways,” wrote Leon Battista Alberti in the 15th century, these “may not improperly be called High Streets.” They are “designed for some certain Purpose, especially a public one; as for instance those which lead to some Temple, or the Course for Races; or to a Place for Justice.” Alberti imagined these grand “public ways” radiating and converging, lined with public buildings of many sorts.

These public avenues, argued Andrea Palladio, would be complex, active and spacious centers of civic life. “Broad Streets are more lightsome,” he wrote, noting “that one side of such a Street is … less eclipsed by the opposite Side. The Beauty of Churches and Palaces must needs be seen to the Greater advantage in large than narrow Streets, whence the Mind is more agreeably entertained and the city more adorned.”

Adorned indeed, and exquisitely right for civic life. The English translators of Alberti and Palladio called their public avenues “High Street” and “Broad Street.” So did Penn, who, in the 1680s, envisioned for “our intended Metropolis” something like the view up Broad Street in the 1890s: a bright, welcoming, urban center, a place that would “never be burnt, and always be wholesome.”