Short answers, pulled from the story.
Donatello, born Donato di Niccolò di Betto Bardi around 1386 in Florence, was an Italian sculptor of the Renaissance period who died on the 13th of December 1466. He was the son of a wool-stretcher who was a member of the Florentine Arte della Lana, and he trained in the studio of Lorenzo Ghiberti before establishing himself as one of the most inventive sculptors of the 15th century.
Donatello's bronze David, now in the Bargello museum in Florence, is his most famous work and the first known freestanding nude sculpture produced since antiquity. It was most likely commissioned by Cosimo de' Medici between 1434 and 1440, and was first recorded in 1469 in the courtyard of the Palazzo Medici.
Stiacciato, meaning "flattened-out," is a type of very shallow bas-relief in which all parts of the composition remain low. Donatello developed this technique to suggest deep space through subtle overlaps rather than varying the height of the carved surfaces. His marble Saint George Freeing the Princess, on the base of his Saint George for Orsanmichele, is described as his first major milestone in the style.
The Equestrian Monument of Gattamelata, placed on the square outside the Basilica of Saint Anthony in Padua, is the first life-size equestrian statue cast in bronze since antiquity. Donatello began designing it in 1443 or 1444 for the heirs of the condottiere Erasmo da Narni, completed the bronze work in 1450, and it was installed on its stone pedestal in 1453. It became the prototype for equestrian monuments across Italy and Europe in the following centuries.
The Medici family were Donatello's most consistent patrons throughout his career, commissioning major works including the bronze David. Cosimo de' Medici gave his blessing to Donatello's decade-long stay in Padua, and Donatello's partnership with Michelozzo benefited from both men's strong ties to the Medici. At the end of his life, Donatello worked on bronze pulpit reliefs for San Lorenzo in Florence, the Medici burial church.
Most of Donatello's major church commissions remain in their original locations or in adjacent church museums. The Bargello in Florence holds the main museum collection including the bronze David. The Victoria and Albert Museum in London holds important shallow reliefs including the Chellini Madonna. The Louvre in Paris and the Berlin State Museums also hold significant pieces.