In what year was the cathedral, that Arnao de Vergara produced several windows for, registered as a World Heritage Site?
Arnao de Vergara:  Between 1525 and 1536 he produced several windows for Seville Cathedral, many of which survive, before later moving to Granada. Seville Cathedral:  It was registered in 1987 by UNESCO as a World Heritage Site, along with the Alcázar palace complex and the General Archive of the Indies.
1987