* 1574 – Cosimo I de ' Medici, Grand Duke of Tuscany ( b. 1519 )

His work at the completion of Pitti Palace, commissioned by Eleonora of Toledo, wife of Cosimo I, is one of his most celebrated achievements ( 1558 – 1570 ), respecting the original style of Filippo Brunelleschi.

He was also named Console of the prestigious Accademia delle Arti del Disegno of Florence, founded by the Duke Cosimo I, at 13 January 1563, under the influence of Vasari.

He took Grand Duke Cosimo I as model for Neptune's face.

The Medici reigned Grand Dukes of Tuscany starting with Cosimo I de ' Medici in 1569, until the death of Gian Gastone de ' Medici in 1737.

* 1519 – Cosimo I de ' Medici, Grand Duke of Tuscany ( d. 1574 )

It was commissioned by Duke Ranuccio I for the visit of Cosimo I de ' Medici.

****** son Cosimo I de ' Medici, Grand Duke of Tuscany married Eleanor of Toledo

Soon after publication, Vesalius was invited as Imperial physician to the court of Emperor Charles V. He informed the Venetian Senate that he was leaving his post in Padua, which prompted Duke Cosimo I de ' Medici to invite him to move to the expanding university in Pisa, which he turned down.

* April 21 – Cosimo I de ' Medici, Grand Duke of Tuscany ( b. 1519 )

* June 12 – Cosimo I de ' Medici, Grand Duke of Tuscany ( d. 1574 )

After a late start, he was ordained priest, and Cosimo I de ' Medici, Grand Duke of Tuscany, sent him as an appropriate ambassador to Pope Pius V, a position which he held for fifteen years.

Cosimo I de ' Medici, Grand Duke of Tuscany | Cosimo I the Great, founder of the Grand Duchy of Tuscany

Power then passed to the " junior " Medici branch — those descended from Lorenzo the Elder, younger son of Giovanni di Bicci, starting with his great-great-grandson Cosimo I the Great.

The most outstanding figure of the 16th century Medici was Cosimo I, who, coming from relatively modest beginnings in the Mugello, rose to supremacy in the whole of Tuscany, conquering the Florentines ' most hated rival Siena and founding the Grand Duchy of Tuscany.

His son Alfonso II married Lucrezia, daughter of grand-duke Cosimo I of Tuscany, then Barbara, sister of the emperor Maximilian II and finally Margherita Gonzaga, daughter of the duke of Mantua.

Building of the palace was begun by Giorgio Vasari in 1560 for Cosimo I de ' Medici as the offices for the Florentine magistrates — hence the name " uffizi " (" offices ").

The project that was planned by Cosimo I, Grand Duke of Tuscany to arrange that prime works of art in the Medici collections on the piano nobile was effected by Francis I of Tuscany, who commissioned from Buontalenti the famous Tribuna degli Uffizi that united a selection of the outstanding masterpieces in the collection in an ensemble that was a star attraction of the Grand Tour.

This weapon is engraved with the personal coat of arms of Cosimo I de ' Medici, Grand Duke of Tuscany.

His son Alfonso II first married Lucrezia, daughter of grand-duke Cosimo I of Tuscany, then after becoming a widower, Barbara, the sister of Maximilian II, Holy Roman Emperor ( 1527 – 1576 ) and finally a third wife, Margherita Gonzaga, daughter of the duke of Mantua.

This exile lasted only until 1512, however, and the " senior " branch of the family — those descended from Cosimo the Elder — were able to rule on and off until the assassination of Alessandro de ' Medici, first Duke of Florence, in 1537.

After her father's assassination in 1537 and the ensuing power struggle among the Medici for control of Florence and of the family, Giulia and her brother Giulio were taken from their mother and placed under the guardianship of Alessandro's successor, Cosimo I de ' Medici.

Alessandro was succeeded by his distant relative Cosimo when he was assassinated in 1537.

Cosimo I ruled over Florence from 1537 to 1569, before being given the title of grand duke.

After the murder of Duke Alessandro in 1537, Guicciardini allied himself with Cosimo de ' Medici, who was just seventeen years old at the time and new to the Florentine political system.

A scandal erupted in 1537, when he was accused of what became known as the ' rape of Fano ', where he allegedly raped the young bishop of the city, Cosimo Gheri, while marching with his troops ( Gheri subsequently died ).

In June 1537, twenty-eight years after Caterina's death, her grandson Cosimo de ' Medici, the only son of her own son Giovanni, became the Duke of Florence and in 1569, the Grand Duke of Tuscany.

Retaining some limited power and influence the family continued to reside at the Palazzo Pitti until finally in 1549 failing fortunes compelled Pitti's descendant Buonaccorso Pitti to sell the palazzo to the Grand Duchess of Tuscany, wife of Grand Duke Cosimo I who re-enforced, the restored but hitherto wavering, power of the Medici in Florence in 1537.

* 1642 – Cosimo III de ' Medici, Grand Duke of Tuscany ( d. 1723 )

* 1469 – Piero di Cosimo de ' Medici of Florence ( b. 1416 )

Galileo initially called his discovery the Cosmica Sidera (" Cosimo's stars "), in honour of Cosimo II de ' Medici ( 1590 – 1621 ).

* 1590 – Cosimo II de ' Medici, Grand Duke of Tuscany ( d. 1621 )

* 1503 – Agnolo di Cosimo, Italian painter ( d. 1572 )

Pope Innocent VII ( probably1339 – 6 November 1406 ), born Cosimo de ' Migliorati, was briefly Pope at Rome between 1404 and 1406 during the period of the Western Schism ( 1378 – 1417 ) while there was a rival Pope, Antipope Benedict XIII, at Avignon.

* 1389 – Cosimo de ' Medici, Italian ruler ( d. 1464 )

* August 14 – Cosimo III de ' Medici, Grand Duke of Tuscany ( d. 1723 )

* September 27 – Cosimo de ' Medici, ruler of Florence ( d. 1464 )

* November 17 – Agnolo di Cosimo, Italian artist and poet ( d. 1572 )

* December 2 – Piero di Cosimo de ' Medici, ruler of Florence ( b. 1416 )

* February 28 – Cosimo II de ' Medici, Grand Duke of Tuscany ( b. 1590 )

* October 31 – Cosimo III de ' Medici, Grand Duke of Tuscany ( b. 1642 )

* April 26 – Giuliano di Piero de ' Medici, son of Piero di Cosimo de ' Medici ( assassinated ) ( b. 1453 )

* January 2 – Piero di Cosimo, Italian artist ( d. 1521 )

* May 12 – Cosimo II de ' Medici, Grand Duke of Tuscany ( d. 1621 )

* August 26 – A conspiracy against Piero di Cosimo de ' Medici, led by Luca Pitti and Borso d ' Este, is discovered and put down in Florence.

* August 1 – Cosimo de ' Medici, ruler of Florence ( b. 1389 )

* September – Cosimo de ' Medici, later the de facto ruler of Florence and patron of Marsilio Ficino, is exiled by the Albizzi / Strozzi faction.