The Most Illustrious

The Most Illustrious or Ilustrísima Señora is an honorific prefix that is traditionally applied to certain people in Spain and certain Spanish-speaking countries. It is a lower version of the prefix The Most Excellent, and was traditionally applied to non-Grandee titled nobles in Spain, but is now used for a series of other offices.

In the Kingdom of Spain

The following State and Government officials receive the style "The Most Illustrious":

Constitutional court and judiciary

The President of the Economic Administrative Central Court
The Lawyers of the Spanish Council of State
Central government
The Finance Delegates
Local authorities
The Headmasters of Secondary State Schools
Diplomacy
The Embassy Counsellors
The Ministers Plenipotentiary of 3rd class
Other institutions
The Director of the Spanish Academy of Rome
The Director of the Spanish Agency of Data Protection
Nobility
Non-Grandee titleholders, their spouses and heirs
Non-firstborn children of Grandees
Other countries

Reference to a Duke in the UK's upper house of Parliament The House of Lords historically employed the prefix "the illustrious Duke" in the late 1800s. In the 21st century, it has been replaced by the generic prefix "the noble Duke" which is customarily used for all members of the House of Lords, irrespective of their rank.

In other countries, "The Most Illustrious" is rarely used, but rather "Illustrious Highness"

The Most Illustrious

In the Kingdom of Spain

Constitutional court and judiciary

Central government

Local authorities

Diplomacy

Other institutions

Nobility

Other countries