Giovanni di Cosimo I de' Medici (29 September 1544 – 20 November 1562), also known as Giovanni de' Medici the Younger, was an Italian cardinal.
He was born in Florence, the second son of Cosimo I de' Medici, Grand Duke of Tuscany, and Eleonora of Toledo. While his elder brother Francesco went on to a political and military career, Giovanni had reserved for him the ecclesiastical career. At the ago of sixteen, he was painted by Bronzino as St. John the Baptist.
Agnolo (di Cosimo) Bronzino, Giovanni de'Medici, Gallery Borghese, Rome
in After having been Archbishop of Pisa, he was created cardinal in Santa Maria in Domnica by Pope Pius IV in the consistory of 31 January 1560, aged only seventeen.
Probably already suffering from tuberculosis, Giovanni died two years after he was made a cardinal in Livorno from a malaria attack. His mother and his brother Garzia died of the latter illness a few days later. Centuries after his death, a myth arose saying that his brother Garzia killed him, following a dispute in 1562. In turn, his father Cosimo, furious, killed Garzia with his own sword. However, modern exhumations showed no signs of violence on the bodies and they were found to have died together of malaria in 1562. His father Cosimo had another son in 1563, who was called by the same name (he is best known as Don Giovanni de' Medici).