Juan Antonio Sánchez Belén, who holds a PhD from UNED, where he is full professor of Modern History, is a specialist in seventeenth- and eighteenth-century Spain, specifically during the reigns of Charles II and Philip V. He has studied the tax system in Castile – on which he has published La política fiscal en Castilla durante el reinado de Carlos II (1996) – the fortune of the royal households, and Dutch trade in Spain in the late seventeenth century, as well as the Royal Chapel of the palace and the sacred oratory in the seventeenth and eighteenth centuries.