This study discusses the development of the altarpiece in sixteenth-century Venice. Focusing closely on Titian's St. Peter Martyr Altarpiece, his most famous work but destroyed in 1867, Patricia Meilman considers how this painting irrevocably changed the course of altar decoration. In order to place it in context, she outlines the types of altarpieces that preceded it and explores its patronage and innovations. Demonstrating the legacy of this altarpiece to a younger generation of painters, which continued well into the seventeenth century, she also examines the social, religious, and historical events of the decades just before the Tridentine reforms and their impact on devotional imagery and practices.