(Bulg. Trioditza, Anc. Sardica), a town of European Turkey, Bulgaria, in a wide plain on the Bogana, at the northern base of the Balkan Mountains, 310 miles W.N.W. of Constantinople. It is a large place, and looks well from a distance, with its castle and numerous mosques, but the houses are in general mean and ill built; and the streets narrow, crooked, and dirty. Besides the mosques and churches, Sophia contains large and well supplied bazaars, khans, and warm baths. The churches belong both to the Greek and Roman Catholics; and the latter have also here two convents. As this town stands on the great high road from Constantinople to Belgrade, it is a place of considerable commerce, which is chiefly in the hands of Greeks and Armenians. Cloth, leather, and tobacco, which are manufactured here, are the chief articles of trade. Sophia was formerly the residence of a pasha, and still gives a title to a Greek archbishop and a Roman Catholic bishop. It was founded by the Emperor Justinian, on the site of the ancient Sardica, and still contains some remains of the church erected by that monarch. Sardica was celebrated for an ecclesiastical council held there in 347, which occasioned some controversy in connection with the papal authority. Pop. 46,000.