Short answers, pulled from the story.
Renaissance art covers the period from approximately 1350 to 1620. It emerged as a distinct style in Italy around 1400 and is considered by art historians to mark the transition from the medieval period to the Early Modern age.
The three great masters of the High Renaissance were Leonardo da Vinci, Michelangelo, and Raphael. Raphael's death in 1520 at the age of 37 is regarded by many art historians as the effective end of the High Renaissance period.
The Medici Bank generated unprecedented wealth for Florence, and Cosimo de' Medici used that wealth to establish a new standard for arts patronage that was independent of the church or monarchy. This freed artists to work for private patrons who valued art on its own terms.
In 1401, Florence held a competition to sculpt a set of bronze doors for the Baptistery of Florence Cathedral, attracting seven young sculptors including Brunelleschi, Donatello, and the winner, Lorenzo Ghiberti. Art historians regard this event as marking the emergence of the first truly Renaissance artists.
Netherlandish painters developed oil paint techniques that were adopted in Italy from around 1475, with lasting effects on painting practices worldwide. When Hugo van der Goes sent his Portinari Altarpiece to Florence in 1475, it immediately influenced Domenico Ghirlandaio, who painted an altarpiece directly imitating its elements.
Sfumato is a painting technique of blurring or softening sharp outlines through the gradual blending of tones using thin glazes, creating an illusion of depth or three-dimensionality. The term was coined by Leonardo da Vinci and derives from the Italian sfumare, meaning to evaporate or fade out.