The Black Army, also called the Black Legion/Regiment – were the military forces serving under the reign of King Matthias Corvinus of Hungary. The ancestor and core of this early standing mercenary army appeared in the era of his father John Hunyadi in the early 1440s. The idea of the professional standing mercenary army came from Matthias' juvenile readings about the life of Julius Caesar. The multinational army, drawing on the earlier Hussite battle tactics, helped to pioneer the concept of a standing mercenary army that would soon be adopted across Europe.