Gian Lorenzo Bernini used hidden windows and yellow-tinted glass to make his marble statues appear to glow with divine light.

Gian Lorenzo Bernini completed 'The Ecstasy of Saint Teresa' between 1647 and 1652 for the Cornaro Chapel in Rome. This work is a prime example of 'bel composto,' a concept where Bernini unified sculpture, painting, and architecture into a single cohesive narrative. The hidden window, known as a 'luce alla veneziana,' is positioned behind the pediment of the altar to remain invisible to the viewer standing in the chapel.The window utilizes yellow-tinted glass to filter natural sunlight, which then reflects off a series of gilded wooden or bronze rays. These rays direct the light downward onto the white Carrara marble figures of the angel and Saint Teresa. Because the light source is hidden, the illumination appears supernatural rather than physical. This technique was a revolutionary development in the Baroque period, emphasizing dramatic contrast and emotional intensity.Art historians, such as those at the Courtauld Institute of Art, note that Bernini meticulously calculated the angle of the sun at different times of the day. This ensured that the sculpture would be bathed in light during specific hours of prayer and liturgy. By manipulating the environment, Bernini transformed the chapel into a theatrical stage where the divine seems to manifest in the physical world. This mastery of light helped define the High Baroque style in 17th-century Italy.