Giotto

Giotto is where European painting starts behaving differently. Before him, figures float against gold in a Byzantine manner. In the Scrovegni Chapel at Padua, painted around 1305, they stand on ground, take up space, have weight, and react to each other.

The Lamentation scene puts mourners with their backs to the viewer, which nobody had done, and the grief reads as physical rather than symbolic. Angels tear at themselves in the sky above.

Vasari built the origin story of the Renaissance around him two centuries later, complete with the tale of Cimabue discovering a shepherd boy drawing sheep on a rock. The biography is thin and much of the attributed work is contested. The chapel is not. It is the clearest surviving evidence of one painter changing the direction of an entire tradition.