The Archbishop's Lyceum is one of the grandest eighteenth-century buildings in Hungary, an enormous Baroque palace constructed between 1765 and 1785 as a university and seminary. The building now houses Eszterházy Károly Catholic University, and two of its rooms are open to visitors: the great library and the observatory-camera obscura on the sixth floor.
The library is outstanding — a two-storey hall of carved wooden bookcases topped by a ceiling fresco depicting the Council of Trent, one of the largest ceiling paintings in Hungary. The observatory above contains instruments from the eighteenth century and the camera obscura, which uses mirrors and a lens to project a live image of the city onto a table in a darkened room. It is a charming piece of Enlightenment technology. The Lyceum faces the cathedral across Eger's main axis and the two buildings together define the monumental scale of the city's historic centre.