COLOCZA (Hung. KALOCSA), ARCHDIOCESE of. — A city of Hungary, in the Pest comitat, seat of the Kalocsa-Bacs archdiocese. The city was founded by St. Stephen in the year 1000, and in the same year the diocese was founded by Sylvester II; it was raised to a metropolitan see in 1135 by Innocent II. In 1242 the entire region and the city were devastated by the Tartars, but King Béla IV rebuilt it a few years later. In 1381 a highly important National Synod in the history of Hungary was held there; the assembled bishops persuaded King Charles Robert of Anjou (1307–42) to return to constitutional government and retract the laws hostile to the Church.
After the disastrous battle of Mohács (1256), C. fell under Turkish rule, and the city itself was completely destroyed in 1690. It rose again, however, after its reconquest by the Christian armies, in 1690. It is now a small cultural and religious center; of its 12,334 inhabitants, 11,537 are Catholics. It has several religious institutes and secondary schools; the library of the Cathedral Chapter contains 85,000 volumes.
Its first bishop was Asztrik, a Benedictine abbot sent by St. Stephen to Pope Sylvester II to announce to him the conversion of Hungary to Christianity. In 1093 the diocese of Bacs was united with that of C., and since several dioceses of Croatia were its suffragans, the struggle against the Patarene and Bogomil heretics had its center at C. (L. Balicus, A rom. hath. Egyház története Magyarországon [La storia della Chiesa catt. r. in Ungh.], III, Budapest 1888, part 2; A. Hodinka, Egyházunk húzdelmei a boszniai eretnehségekkel [Le lotte della nostra Chiesa contro le eresie della Bosnia], Kolocza 1902).
Archbishop Paolo Tomory was the commander of the Hungarian army at the battle of Mohács and lost his life there. Until the Romanian concordat (1929), the dioceses of Csanád, the Latin-rite portion of Nagyvárad (Gran Varadino), and Transylvania were suffragans of C. (the last two became autonomous after the concordat).
The archdiocese covers 13,000 sq. km., with 357 diocesan priests and 45 religious priests; it has 606,000 Catholics out of a population of 880,000 (1948).