Austrian, 'The Trinity with Christ Crucified', about 1410

This large painting shows the three divine beings of the Trinity: God the Father, seated on an enormous white throne, supports his son, Christ, shown on the Crucifix on which he was killed; he seems minute by comparison. The Holy Ghost is represented by a dove that hovers between the two figures. On each side of the throne an angel kneels in adoration.

The simple colour scheme of green, red and white is striking against the gilded background. The design is symmetrical but the arrangement of the colours is asymmetrical: the angels have alternating red and green wings and robes. Their patterned robes emulate damask and contrast with the austere simplicity of the throne. Their decoration was created using imitation sgraffito, applying glazes of paint over areas of gilding, leaving some parts uncovered to create the patterns. This replicated the visual effects of the Italian sgraffito technique, where a layer of gold leaf was covered entirely by paint which was then scratched away in areas to reveal the metal beneath. The inscriptions on the scrolls crossed around the angels' necks were not intended to be legible. The reverse is painted with green tendrils of foliage against a white background.

The panel once formed the central part of an altarpiece with panels on either side – the hinge marks are still visible on either side of the frame, which is original to the picture. The side panels – or shutters – would protect and conceal the image when closed. Four panels in Rastenberg Castle, Austria have been identified as the side panels originally connected to our panel. They show the Virgin, standing, holding the Christ Child; Saint Stephen holding a stone- a reminder that he was stoned to death; a nun-Saint, possibly Saint Clare, holding a skull and Saint Lawrence.

It has been suggested that the Virgin and Saint Stephen may have formed the inner side panels, closest to the central image, while Saint Lawrence and the female saint may have been the outer panels, as they are of a slightly lower quality. The identity of the artist has not yet been discovered but other works have been connected with this one, and the painter is sometimes known simply as the Master of the London Throne of Mercy.