In 'Love's Labour's Lost', Ferdinand is the king of Navarre who leads the vow of study.
At the beginning of Shakespeare's comedy, Ferdinand and his three companions—Berowne, Longaville, and Dumaine—swear to spend three years studying and fasting, avoiding the company of women. The vow is immediately tested when the Princess of France and her ladies arrive on a diplomatic mission concerning Aquitaine. Because women are barred from the court, the visitors must camp outside its walls.
Ferdinand and his companions soon fall in love with the women they promised to avoid. Their attempts to conceal their feelings produce the play's elaborate wordplay, disguises, letters, and comic reversals. The king courts the Princess of France, while Berowne, Longaville, and Dumaine pursue Rosaline, Maria, and Katharine.
The character is fictional within the play, though Shakespeare's Navarrean setting echoes the historical Henry of Navarre, who later became Henry IV of France. Ferdinand is the king; Berowne, Longaville, and Dumaine are his attending lords.