The two young Florentines made drawings of almost every building in Rome and others beyond the walls. They measured widths and estimated heights of entablatures and roofs, drawing elevations on parchment graphs with numbers and symbols which Filippo alone understood. Earning money as goldsmiths, they hired porters and laborers to excavate monuments and better better examine their structure. The Romans called them "treasure hunters," believing they were digging for ancient silver, gold, or precious stones. But the treasure they sought was more precious than these, for it was the treasure of ancient knowledge, lost in the dark centuries that followed the fall of Rome, and it was this treasure that Filippo carried with him when he returned to Florence a new man - no longer a sculptor, but an architect, a man of such sweeping vision and original genius that he is rightly called the father of the Renaissance.
-a story, perhaps a legend, related by Paul Robert Walker in The Feud That Sparked the Renaissance: How Brunelleschi and Ghiberti Changed the Art World