 Both scholars were acting as servants of their masters King Ferdinand II and the Duke of Alba when they accepted these propaganda assignments, as pointed out by the historian Alfredo Floristan.López de Palacios would later develop the doctrine legitimizing the Spanish conquest of the West Indies.In late August 1512, once the conquest of the heartland of Navarre was completed, Ferdinand issued a statement defending his right to attack Navarre according to the "iure belli" or "fair war" doctrine passed by the Roman Church in 1511.