File:Martirio de San Andrés, por Juan Correa de Vivar.jpg

Summary
A painting by Juan Correa de Vivar (1510-1566) depicting the death of St. Andrew on a diagonal X shaped cross.

https://commons.wikimedia.org/wiki/File:Martirio_de_San_Andr%C3%A9s,_por_Juan_Correa_de_Vivar.jpg