2. Hieronymus Bosch - The Garden of Earthly Delights

The Garden of Earthly Delights by Hieronymus Bosch, painted c.1505. This imposing work, full of strange and fantastical details, contains one of the most famous images in all of art: a man with a tree for a body, who gazes out at us from the section of the painting representing hell. The tree-man's face is generally thought to be the artist's self-portrait but, like almost everything else about Hieronymus Bosch - including the meaning of this, his most famous painting - no one knows for sure.

3. Piero Della Francesca - Baptism of Christ

The Baptism of Christ by Italian master Piero Della Francesca showed the household names of the High Renaissance how to use the big new trick of Renaissance painting - illusionism and perspective. Without him their achievements would have been impossible, but change came so rapidly in the Renaissance that the qualities that made Piero famous in his own time quickly went out of fashion.