The "King of Navarre" refers to the monarch of the historical region of Navarre, located in northern Spain and southwestern France. This kingdom played a significant role in medieval European politics and was known for its unique culture and language, Basque. The title has been held by various rulers throughout history, with notable kings such as Sancho VI and Henry IV of France. In the 16th century, the Kingdom of Navarre faced challenges from neighboring powers, leading to its eventual annexation by Spain in 1512. Despite this, the title of King of Navarre continued to be used by descendants of the royal family, symbolizing the region's rich heritage and historical significance.