The stunning island of Palmarola is the second-largest island in the Pontine archipelago. Due to its steep cliffs and spectacular rugged landscape, the island is mostly uninhabited during the year except for the summer months. The French oceanographer Jacques-Yves Cousteau described it, "as the most beautiful island in the Mediterranean Sea".

In the past, the islanders of Ponza would farm Palmarola and seek shelter from corsairs in their cave dwellings, which were built into the volcanic rock above the island's only accessible bay.

The island became a prison for the exiled Pope Silverius, who was sent here by the Byzantine General Belisarius at the time of the Gothic War. He had been falsely accused of attempting to open the gates of Rome to the Gothic army. He died on the island and according to tradition, in the same spot where the present-day chapel was erected. 

Inside the tiny chapel, a statue of the saint is surrounded by pictures and ex-voto offerings by the inhabitants of Ponza. The statue only leaves the chapel on the 20th of June, when the inhabitants of Ponza sail to Palmarola and return the statue to the larger island for a three-day festival in his honor.

The chapel can only be reached from the sea and after a steep hike on a vertical path that leads to the top of the sea stack, which offers spectacular views.