The central European heads of state visited a museum which is part of the castle that was built in the 13th century and whose present design dates back to the 19th century.
After the tour of the castle, the guests attended a dinner organised in their honour by Croatian President Stjepan Mesic.
A plenary session dedicated to European Union enlargement was held earlier in the day, with participants confirming the commitment of EU countries to continue the enlargement process to cover Southeast Europe and the wish and commitment of candidate countries and countries aspiring to the join the EU to enter the bloc.
Presidents Carlo Azeglio Ciampi of Italy, Georgi Pervanov of Bulgaria, Traian Basescu of Romania, Valdas Adamkus of Lithuania, and Svetozar Marovic of Serbia and Montenegro left Croatia today.
The summit will continue on Saturday with a plenary session dedicated to the economic and social aspects of EU enlargement.