Wasn t just based on profit, but loyalty as well. remains loyal to medici bank. y cossimo and father (giovanni) attempted to discover solution to dome: brunelleschi. 1419 built building using arches and classic greek and roman structural. In medici, found patrons willing to gamble on his judgement designs for first time since ancient times. medici tried to be patron of his work: creation of dome. government offered huge cash prize for solution y was given to brunelleschi. wrote designs in code in fear of them being stolen. recipe for concrete had been lost since fall of rome. Inspired by greek pantheon. y would have to support itself completely on own. as construction progressed, giovanni the medici s health declined died in 1429. y hands of medici dynasty left in cossimo s hands: 1433, cossmi summoned to the palace of the government. abici (enemy s of medici) waiting for him.