Unknown Artist - The Darnley Portrait of Queen Elizabeth I

Federigo Zuccaro (1540-1609) - The Darnley Portrait (Queen Elizabeth I) (1575)
Great Britain 4d Stamp Issued 1968
National Portrait Gallery, London

Note that this artist may not have been the painter of this important portrait of the queen, which was almost certainly created by the artist through a live sitting with the queen at the time.  This portrait is said to have started a trend in the composition of images of the virgin queen - she is portrayed in a very regal and serious manner, with pale features and ornate garments.

Lorenzo Lotto - The Nativity

Lorenzo Lotto (1480-1566) - The Nativity (1525)
USA 6c Stamp Issued 1970
Painting Held at the National Gallery of Art, Washington DC 

Lotto has been traditionally been placed in the Venetian School of high renaissance art, although it is said that his work was rather eccentric at times, showing a transition to the first Florentine movements and Rome mannerist paintings of the 16th Century.

As a Venetian painter, it is clear that Lotto was influenced by Bellini.  

He also worked in the same time as the following artists:

Albrecht Durer

Raphael

Titian