It is a phenomenon observed in all multicultural empires, not just in the Spanish Empire

The black legend of empires would be the result of the following combined factors:

• The combined propaganda attacks and efforts of most smaller powers of the time, as well as defeated rivals.
• The propaganda created by the many rival power factions within the empire itself against each other as part of their struggle to win more power.
• The self-criticism of the intellectual elite, which tends to be larger in larger empires.
• The need of the new powers consolidated during the empire's life or after its dissolution to justify their new prevalence and the new order.