Zagreb, as we know it today, was built in the Middle Ages on two hills, the secular Gradec, the current Upper Town, and the ecclesiastical Kaptol. The first written source dates from 1094, when King Ladislav founded the Zagreb diocese on Kaptol.
Zagreb Cathedral or Cathedral of the Assumption of Mary and Saints Stephen and Ladislaus is the cathedral of the Archdiocese of Zagreb and the largest church in Croatia. It is dedicated to the Assumption of Mary and to the Hungarian kings Saint Ladislaus I and Saint Stephen. The construction of the sacral building began with the establishment of the Zagreb diocese in the Romanesque-Gothic style. Its construction took quite a long time, so it was completed and consecrated in 1217. In 1242, it was badly damaged by the invasion of the Mongols, but Bishop Timotej (1263-1287) began to restore it in the Gothic style. The restoration of the cathedral continued in the 14th and 15th centuries. In the 16th century, the Zagreb Cathedral was fortified with walls and towers, and in the 17th century it was given a Renaissance bell tower. It was damaged several times due to enemy invasions and fires, and it suffered the most damage in the earthquake of 1880. After this earthquake, the cathedral was restored in the neo-Gothic style (1880-1906). The plans were made by the Austrian architect Friedrich von Schmidt, and the restoration work was led by Hermann Bolle. At that time, the church got its present appearance with a high roof, two bell towers and new columns and altars, which replaced the baroque ones from the 18th century. A new tomb for the Archbishops of Zagreb was built behind the main altar, replacing the old tombs of bishops and holders. The following are buried in the cathedral: Croatian martyrs Fran Krsto Frankopan and Peter Zrinski, Evgen Kvaternik, Ivan Anton Zrinski and others.
The last three blessed archbishops of Zagreb, Alojzije Stepinac, Franjo Seper and Franjo Kuharic, are also resting in the cathedral. In June 2011, the cathedral was visited by Pope Benedict XVI, who prayed at the grave of Alojzije Stepinac.