Painting on stone and its creator

Sebastiano del Piombo, who discovered how to paint in oil on stone, painted many large portraits on slate, and, following his example, so did some contemporary painters. The sitters are usually worthy of commemoration, for example for their military victories, like Baccio Valori. Orazio Piatesi, possibly the youth portrayed by Daniele da Volterra, was also appreciated for his learning and for his valor. In the unfinished portrait of Clemente VII, we can read an allusion to his role as Peter’s successor, the rock (pietra in Italian) upon which Christ founded his church. These figures’ bulkiness reminds us that painting on stone, especially in the Sixteenth century often meant to challenge sculpture.

The portraits of Cosimo I de’ Medici and of two Strozzi brothers, fierce enemies of his, are instead very small. Cosimo’s likeness on red porphyry, one of the many versions of Bronzino’s original, means to convey not only the Grand-duke’s power, given the stone was associated to Roman emperors, but also his supposed role in the discovery of how to carve it, mentioned by Vasari. In the support we can also read the wish that the power of the Medici family would last as long as porphyry, known for its hardness.

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