The Most Illustrious (Spanish: IlustrÃÂsimo Señor (male) or IlustrÃÂsima Señora (female), literally "Most Illustrious Lord/Sir") 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 (ExcelentÃÂsimo/a Señor/a), and was traditionally applied to non-Grandee titled nobles in Spain, but is now used for a series of other offices.
The following State and Government officials receive the style "The Most Illustrious":
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 In the 21st century, it has been replaced by the generic prefix "the noble Duke" which is customarily used for all members of the House of Lords, irrespective of their rank.<br /> In other countries, "The Most Illustrious" is rarely used, but rather "Illustrious Highness"