During Roman times the circular opening in the rotunda was left open allowing the rain to fall into the tepid water below.

When the Baths were transformed the opening needed to be changed as a Roman bathhouse is quite different to a Church.

Michelanglo and Vanvitelli erected lanterns in the opening but these were subsequently demolished.

During the 20 th century a series of sky lights were installed but these proved to be unsuitable and vulnerable to bad weather.

The installation of this modern glass dome results from a succession of actions and decisions taken by a group of innovators who by working together were able to create this extraordinary masterpiece.

Maurizio Calvesi summarizes this achievement thus: “We cannot generalise modern intervention in antique works and indeed we should perhaps continue to avoid it; but this is a particular case where the artist chosen is a world leader in the field of stained glass and he is undoubtedly happy.”