Bronze door: Martyrdom of St Peter

The depiction of the crucifixion of St Peter on a mountain between two pyramids, the Castel Sant'Angelo and a tree, shows a mixture of various medieval and contemporary interpretations of the tradition of the crucifixion 'inter duas metas'.

There was a very popular belief that lasted throughout the Middle Ages, according to which St Peter had been crucified inter duas metas, i.e. between two monuments, both of which identified as a meta. Representations of the Crucifixion of St Peter from the 13th-15th centuries illustrate this tradition, as seen from the paintings of Cimabue in the Upper Church, San Francesco, Assisi, Giotto in the Stefaneschi Triptych, Deodato di Orlandi in San Piero a Grado, Pisa, or Masaccio in the Pisa Altarpiece.