Cosimo de Medici (1389 – 1464) was an Italian banker and politician, the first of the Medici political dynasty, de facto rulers of Florence during much of the Italian Renaissance. The Medici family produced four popes (Leo X, Clement VII, Pius IV and Leo XI), two queens (Catherine de’ Medici and Marie de’ Medici), and many other influential people.

Cosimo de Medici was born in Florence, the son of Giovanni di Bicci de’ Medici and his wife Piccarda Bueri. He had a twin brother, Damiano, who died shortly after birth. Cosimo also had two older brothers, Lorenzo the Elder and Giuliano, who were five and three years older respectively. When Cosimo was eight, his father Giovanni was exiled from Florence as a result of the machinations of his political rivals. He died soon afterwards in 1428. By this time, Cosimo had already been sent to study at the Monastery of Santa Maria Maddalena in Florence’s olive groves.

When Cosimo’s father died, his mother Piccarda Bueri took over the family bank. She proved to be an able and astute businesswoman, increasing the bank’s profits tenfold. Cosimo inherited the bank when he turned 21, and quickly set about making it one of the most successful in all of Europe. He also expanded the family’s business interests into other areas, including agriculture, shipping, and wine-making.

Cosimo was a generous patron of the arts, commissioning works by some of the most famous artists of his day, including Leonardo da Vinci and Michelangelo. He also helped to finance the construction of many important buildings in Florence, including the Cathedral of Santa Maria del Fiore and the Palazzo Vecchio.

In 1434, Cosimo was elected as one of the gonfalonieri, or standard-bearers, of Florence. This was a prestigious position that gave him a leading role in the city’s government. He would go on to hold a number of other important political positions over the next few years.

In 1464, Cosimo de Medici died at the age of 75. He was succeeded by his son Piero, who would become the second head of the Medici family dynasty.