From Wikipedia

A History Of European Art
Lecture Nineteen

High Renaissance Painting in Venice

Giovanni Bellini

Giovanni Bellini was the exact contemporary of his brother Gentile, his brother-in-law Mantegna and Antonello da Messina. Working most of his life in the studio of his brother, and strongly influenced by the crisp style of Mantegna, he does not appear to have produced an independently signed painting until he was in his late 50s. During the last 30 years of his life he was both extraordinarily productive and influential, having the guidance of both Giorgione and Titian.

Madonna and Child with Saints by Giovanni Bellini.

Bellini, like his much younger contemporary, Raphael, produced numerous small Madonnas in rich glowing colour, usually of more intense tonality than his Florentine counterpart. These Madonnas multiplied prolifically as they were reproduced by other members of the large Bellini studio, one tiny picture, the Circumcision of Christ existing in four or five almost identical versions.

Traditionally, in the painting of altarpieces of the Madonna and Child, the enthroned figure of the Virgin is accompanied by saints, who stand in defined spaces, separated physically in the form of a polytych or defined by painted architectural boundaries. Piero della Francesca used the Classical niche as a setting for his enthroned Madonnas, as Masaccio had used it as the setting for his Holy Trinity at Santa Maria Novella. Piero grouped saints around the throne, in the architectural space.

Bellini used this same form, known as Sacred conversations, in several of his later altarpieces such as that for the Venetian church of San Zaccaria. It is a masterful composition which extends the real architecture of the building into the illusionistic architecture of the painting, making the niche a sort of loggia opened up to the landscape and to daylight which streams across the figures of the Virgin and Child, the two female saints and the little angel who plays a viola making them brighter than the two elderly male saints who stand to the fore in the picture, Peter deep in thought and Jerome immersed in a book.

Sleeping Venus by Giorgione.Giorgione and Titian

Whilst the style of Giorgione's painting clearly relates to that of his presumed master, Giovanni Bellini, his subject matter makes him one of the most original and abstruse artists of the Renaissance. One of his paintings, of a landscape known as the Tempest, with a semi-naked woman feeding a baby, a clothed man, some classical columns and a flash of lightning, perhaps represents Adam and Eve in their post-Eden days, or perhaps it doesn't. Another painting, called the Philosophers may represent the Magi planning their journey in search of the infant Christ, but this is not certain either. One thing that appears to be certain is that Giorgione painted a female nude, the very first female nude that stands, or rather, lies, as a subject to be portrayed and admired for beauty alone.

Portrait of a Venetian by Titian.

There are no need for Classical references in this painting, although in later nudes Titian, Velazquez, Veronese, Rembrandt, Rubens and even Manet saw fit to add some. They are the artistic heirs of Giorgione's nude.

On his premature death, Titian completed the painting and went on to paint a great more naked women, most frequently, as Botticelli did, disguising them as goddesses and surrounding them with sylvan woods and starry skies to make perfect decoration for the walls of rich clientele. But it was as a painter of portraits that Titian excelled, his longevity allowing him to achieve far more, both in the way of production and in stylistic development than either Giorgione or his Florentine contemporary Raphael were able to. Titian gave the world images of Pietro Aretino and Pope Paul III and many other people of his day, perhaps his most powerful portrait being that of Doge Andrea Gritti, ruler of Venice, who looms large in the picture space, one huge hand clasping his heavily-buttoned robe in a dynamic Expressionistic gesture. Titian is also renowned for his religious painting, his last work being a turbulent and abstracted Pieta.