Having passed through the only entrance, there are six steps down to the chapel itself.
The chapel has a coffered barrel vault ceiling which gives it a sense of majesty. On the back wall, where the altar used to stand, there are three simple niches and, on each side of them, two smaller carved ones.
At the four angles of the chapel there are Doric-style pilasters creating a corner, with their corresponding friezes of triglyphs and metopes carved in stone into the side walls and painted on the altar wall.
Part of the original paving is still in place today.