The document discusses the Mannerist style of art and architecture that emerged in the 16th century in Florence and Rome as a reaction against the ideals of the High Renaissance. Some key features of Mannerism include elongated proportions, asymmetrical and irregular compositions, and an emphasis on complex poses and artificial effects rather than balance and rational order. Mannerist works also featured unusual lighting, expressive forms, and a revival of elements of Roman architecture. The style represented a shift away from the naturalism, symmetry, and classical restraint of the Renaissance in favor of a more complex, anti-structural, and exaggerated mode of expression.