The St. Thecla Altarpiece in Burgos Cathedral
In the legends St. Thecla gained protection from the fire by making the sign of the cross. In the images, this act is represented by her holding a physical cross in her hand. That appears to be what is happening here.
The Iconian servants of the Thecla story are here dressed as Moors, and at the altarpiece's high pinnacle we see Moors in similar attire being trampled by Santiago Matamoros, St. James the Moor-killer.
Trees identical to those represented in this work may be seen in the riverside promenade near the cathedral.
Read more about St. Thecla.
Photographed at the cathedral by Richard Stracke, shared under Attribution-NonCommercial-ShareAlike license.