Titian's Death of Peter Martyr (1530, destroyed by fire in 1867) was, for three centuries, unanimously considered the greatest altarpiece of the 16th century - a work that Vasari, Dolce, Aretino, and virtually every art critic of the period placed at the summit of Renaissance painting. Its loss to fire in 1867 is one of the most lamented catastrophes in the history of Western art; we know it only through copies, engravings, and the testimony of witnesses who describe it with a reverence normally reserved for sacred objects themselves.
The subject was Peter of Verona (1205-1252), a Dominican inquisitor murdered by Cathar assassins in a forest near Milan. His two-word response as he lay dying - writing 'Credo' (I believe) in his own blood - made him one of the most celebrated martyrs of the medieval Church and a hero of Dominican spirituality. Titian's commission, for the Dominican church of Santi Giovanni e Paolo in Venice, asked him to paint the moment of murder: the assassin's blow, the fleeing companion, and the response of heaven.
What Titian created, according to all who saw it, was a painting that transformed the violence of martyrdom into an epiphany. The forest setting - unusual for an altarpiece, setting natural rather than architectural space as the theater of divine drama - allowed him to use the breaking sky and descending angels as a visual register of heaven's response to the martyr's death. The assassin's raised arm and the fleeing companion created a diagonal of human terror that was answered by the descending diagonal of the angels, creating a composition of extraordinary formal tension and spiritual resolution.
Theologically the painting drew on two key scriptural moments. Revelation 6:9-11 presents the souls of martyrs under the altar, crying 'How long, Sovereign Lord, holy and true, until you judge the inhabitants of the earth and avenge our blood?' - and receiving the answer that they must wait until the full number of martyrs is complete. Acts 7:55-60 depicts Stephen's martyrdom with the same visual structure: the earth-level violence and the heaven-opening vision coincide, as Stephen looks up and sees the glory of God. Peter Martyr's death, in Titian's interpretation, participates in this pattern: the moment when the blow falls is simultaneously the moment heaven opens.
The painting's influence on subsequent Baroque art - on Rubens, Van Dyck, and Caravaggio's martyrdom paintings - was enormous. Every major altarpiece of the Counter-Reformation that depicted a saint's death owes a formal and theological debt to Titian's lost masterpiece. The combination of earthly violence and heavenly opening, the forest setting as moral wilderness, the diagonal composition that links human suffering to divine response - all became standard features of Baroque sacred painting because Titian had discovered them here.
That such an influential work exists only in memory and reproduction adds a strange dimension to its afterlife: like the martyrs it depicted, it survives primarily through the testimony of those who witnessed it.