a city in France, in the department of the lower Pyrenees, and before the Revolution, a bishop's see. Its population in 1800 was 6733. The cathedral is a wretched edifice, very ancient, built in a barbarous style, and almost in ruins. The remains of the castle of Orthez are very noble, and its situation is fine, on a hill which commands the town and a great extent of country. The people call it Le Chateau de la Reine Jeanne, because that queen resided in it during many years, in preference to the castle of Pau. The princess Blanche, daughter to John king of Arragon and Navarre, was shut up, and died here, in 1464. Her brother being dead, she became heiress to the crown of Navarre; but her father having delivered her into the hands of her younger sister Leonora countess of Foix, she confined the unhappy Blanche in the castle of Orthez, and, after an imprisonment of two years, caused her to be poisoned.