Most people do not mind being surpassed in good fortune, character, or temperament, but no one, especially not a sovereign, likes to be surpassed in intelligence. For this is the king of attributes, and any crime against it is lèse-majesté.

[Bien se hallará quien quiera ceder en la dicha, y en el genio; pero en el ingenio, ninguno, cuanto menos una soberanía. Es éste el atributo rey, y así cualquier crimen contra él fue de lesa Majestad.]

Baltasar Gracián y Morales (1601-1658) Spanish Jesuit priest, writer, philosopher

The Art of Worldly Wisdom [Oráculo Manual y Arte de Prudencia], § 7 (1647) [tr. Maurer (1992)]
    (Source)

See Johnson. (Source (Spanish)). Alternate translations:

There are many who will yield in good fortune, or in good humour; but no body will yield in Wit, and least of all a Sovereign. Wit is the King of Attributes, and by consequent, every Offence against it, is no less a Crime than Treason.
[Flesher ed. (1685)]

There be some that will grant you precedence in good luck or good temper but none in good sense, least of all a prince; for good sense is a royal prerogative, any claim to that is a case of lèse-majesté.
[tr. Jacobs (1892)]

Some will deign to take place after you in matters of luck or of heart, but in intelligence, none, least of all a sovereign: for this is the sovereign attribute, wherefore any attack upon it is a crime against majesty.
[tr. Fischer (1937)]