In his own life he had pursued this course of conduct, acquiring a reputation for civic moderation and impartiality that endeared him to the people and stood his children in good stead.  Early in his youth Giovanni found himself almost destitute by reason of the imposts charged upon him by the oligarchs.  He possessed, however, the genius for money-making to a rare degree, and passed his manhood as a banker, amassing the largest fortune of any private citizen in Italy.  In his old age he devoted himself to the organisation of his colossal trading business, and abstained, as far as possible, from political intrigues.  Men observed that they rarely met him in the Public Palace or on the Great Square.

Cosimo de’ Medici was thirty years old when his father Giovanni died, in 1429.  During his youth he had devoted all his time and energy to business, mastering the complicated affairs of Giovanni’s banking-house, and travelling far and wide through Europe to extend its connections.  This education made him a consummate financier; and those who knew him best were convinced that his ambition was set on great things.  However quietly he might begin, it was clear that he intended to match himself, as a leader of the plebeians, against the Albizzi.  The foundations he prepared for future action were equally characteristic of the man, of Florence, and of the age.  Commanding the enormous capital of the Medicean bank he contrived, at any sacrifice of temporary convenience, to lend money to the State for war expenses, engrossing in his own hands a large portion of the public debt of Florence.  At the same time his agencies in various European capitals enabled him to keep his own wealth floating far beyond the reach of foes within the city.  A few years of this system ended in so complete a confusion between Cosimo’s trade and the finances of Florence that the bankruptcy of the Medici, however caused, would have compromised the credit of the State and the fortunes of the fund-holders.  Cosimo, in a word, made himself necessary to Florence by the wise use of his riches.  Furthermore, he kept his eye upon the list of burghers, lending money to needy citizens, putting good things in the way of struggling traders, building up the fortunes of men who were disposed to favour his party in the State, ruining his opponents by the legitimate process of commercial competition, and, when occasion offered, introducing new voters into the Florentine Council by paying off the debts of those who were disqualified by poverty from using the franchise.  While his capital was continually increasing he lived frugally, and employed his wealth solely for the consolidation of his political influence.  By these arts Cosimo became formidable to the oligarchs and beloved by the people.  His supporters were numerous, and held together by the bonds of immediate necessity or personal cupidity.  The plebeians and the merchants were all on his side.  The Grandi and the Ammoniti, excluded from the State by the practices of the Albizzi, had more to hope from the Medicean party than from the few families who still contrived to hold the reins of government.  It was clear that a conflict to the death must soon commence between the oligarchy and this new faction.