The Series Historic Buildings in Transylvania, launched in 1993, presents the most precious examples of Transylvanian built heritage connected to the Hungarian culture, with the purpose of drawing the general public's attention on values, heritage and our responsibilities towards these. The publications of this series are recommended especially to those who at present own or use such values, but also to those who are interested in history, architecture and the Transylvanian art.

Number 40 of the Series Historic Buildings in Transylvania presents the fortress of Oradea, a settlement placed on the riverbanks of Crişul Repede. The mediaeval fortress, together with the cathedral and the bishop's palace inside it, founded according to tradition by St. Ladislaus, were torn down during the 17^th century, and then rebuilt on the purpose of setting a princely court. The present monumental ensemble is dominated by the Renaissance buildings dating from the times of the Transylvanian Principality. Within the pentagonal fortress protected by Italian-type bastions placed in its corners, stands the pentagonal princely palace, in the interior of which recently there have been discovered richly decorated stuccoes. The rehabilitation works of the castle began in  2002.