Juan II de Castilla

Juan II de Castilla, who reigned from 1406 to 1454, was a significant monarch in the history of Spain, known for his efforts to consolidate royal power and improve the administration of justice. His introduction of the medical internship system through the Laws of Toro in 1371 was pivotal in establishing regulatory frameworks for the medical profession in Spain, ensuring that physicians had the necessary credentials and skills to practice medicine.