ORTHEZ, a town of south-western France, capital of an arrondissement in the department of Basses-Pyrénées, 25 m. N.W. of Pau on the Southern railway to Bayonne. Pop. (1906) town 4159; commune 6254. It is finely situated on the right bank of the Gave de Pau which is crossed at this point by a bridge of the 14th century, having four arches and surmounted at its centre by a tower. Several old houses, and a church of the 12th, 14th and 15th centuries are of some interest, but the most remarkable building is the Tour de Moncade, a pentagonal tower of the 13th century, once the keep of a castle of the viscounts of Béarn, and now used as a meteorological observatory. A building of the 16th century is all that remains of the old Calvinist university (see below). The hôtel de ville is a modern building containing the library.
Orthez has a tribunal of first instance and is the seat of a subprefect. The spinning and weaving of cotton, especially of the fabric called toile de Béarn, flour-milling, the manufacture of paper and of leather, and the preparation of hams known as jambons de Bayonne and of other delicacies are among its industries. There are quarries of stone and marble in the neighbourhood, and the town has a thriving trade in leather, hams and lime.
At the end of the 12th century Orthez passed from the possession of the viscounts of Dax to that of the viscounts of Béarn, whose chief place of residence it became in the 13th century. Froissart records the splendour of the court of Orthez under Gaston Phoebus in the latter half of the 14th century. Jeanne d'Albret founded a Calvinist university in the town and Theodore Beza taught there for some time. An envoy sent in 1569 by Charles IX. to revive the Catholic faith had to stand a siege in Orthez which was eventually taken by assault by the Protestant captain, Gabriel, count of Montgomery. In 1684 Nicholas Foucault, intendant under Louis XIV., was more successful, as the inhabitants, ostensibly at least, renounced Protestantism, which is nevertheless still strong in the town. In 1814 the duke of Wellington defeated Marshal Soult on the hills to the north of Orthez.