Short answers, pulled from the story.
The High Renaissance was a short period of exceptional artistic production in the Italian states, particularly Rome and Florence. Most art historians place its start between 1490 and 1500, with common end dates proposed as 1520, 1525, 1527, or 1530, depending on the scholar.
The best-known figures are Leonardo da Vinci, Michelangelo, Raphael, and Bramante, who worked across painting, sculpture, and architecture. Even painters considered minor in the period, such as Fra Bartolomeo and Mariotto Albertinelli, produced work later praised for its harmony.
Jacob Burckhardt coined the German term Hochrenaissance in 1855. The concept drew on Johann Joachim Winckelmann's 1764 description of a High Style in painting and sculpture from the early sixteenth century.
Scholars disagree on the endpoint. The most widely cited date is 1520, when Raphael died. Others point to the Sack of Rome in 1527, when the army of Charles V, Holy Roman Emperor, killed and dispersed many artists, or to 1532, when the Republic of Florence ended.
Frederick Hartt identified Leonardo da Vinci's The Last Supper, painted between 1495 and 1498, as the work that broke decisively from the Early Renaissance. Christoph Luitpold Frommel agreed it was the first High Renaissance work, while also noting that Michelangelo's Pietà, executed in 1498-99, falls within the same founding period.
High Renaissance painting combined linear perspective, realistic depiction of physical and psychological features, sfumato (the softening of colour transitions), and chiaroscuro (contrast between light and dark) into a single style. The goal was total compositional order, balance, and harmony across the whole painting.