The Zagreb parliament is an authority, which takes a part in the Croatian political development since the Middle Ages. The gap between 1910–1920 is an important spell of time for this class authority, due to its commitment with the World War I. The war has decreed the destiny of the Croatian state system. The main questions are about the way of constituting the council, its rights and its position concerning the Croatian national issue during 1910–1920. Substantial resources in Bulgarian are used for composing the specified problem.