Two bronze panels, created by Ghiberti and Brunelleschi around 1401, were submitted by these respective artists as part of the compeition to see who would create the rest of the panels on the baptistery doors of the Florence baptistery.  This competition is generally considered to mark the beginning of the Renaissance period in Italy.A peek behind Florence’s “Gates of Paradise”You can see in some of the photos in the link how Ghiberti (who won the competition) created his panel out of a single piece of bronze (that is, he single-casted it).  Brunelleschi, on the other hand, cast different parts for his panel separately.  The end result was that Ghiberti's used less bronze, and was less expensive to make.