The Renaissance: Florence Leads the Way - The Wise World Traveler: Becoming a Part of All that You Meet - page 99

of a Venetian bank that underwrote the country's exploration. And most important, they in-
vented the basic tool of modern accounting, double-entry bookkeeping.
AN ARCHITECTURAL WONDER
The citizens of Florence began building a cathedral in 1296, but the 180-foot vertical walls
were not ready for a dome until 1418. Architects of Florence tried to rediscover how Rome
had built the dome of the Pantheon. But a dome for the Cathedral of Florence was a daunt-
ing project. To enclose the roof opening over the apse, a dome would have to span 185.5
feet across. No trees of sufficient size or strength were available to build either a framework
to support a dome's weight and size or to follow the ancient Roman technique of building
a “formwork” to which brick and stone could be attached. Equally daunting, the weight of
a dome pushing down and outward on the cathedral's walls was likely to send the walls
crumbling to rubble and dust.
But the problem of the dome gave way to the genius of one of Florence's “Renaissance
Men,” Filippo Brunelleschi (13771446). Brunelleschi was a painter, a sculptor, a metallur-
gist who worked in bronze, a mathematician, a designer of complex machines, and an ar-
chitect. His design for the dome embodied five bold ideas. First, to make the dome's marble
and brickwork manageable, he proposed an octagon design. Second, to reduce weight, the
roof opening would be covered by two domes, one inside the other, joined by supporting
arches and spans. Third, each section of each dome would be secured and given its form
by a stone rib, twenty-four in all, rising upward and curving inward to form a small circle
held in place by an iron ring. Each rib would be seven feet thick at its base, tapering to
five feet at its top. Fourth, the space inside each rib would be built of stone and brick rising
upward in horizontal courses to provide structural strength. And fifth, the ribs comprising
each dome would be held in place by a horizontal circle of stone and iron.