In Russia, Zemsky Sobor existed from the mid 16th century to the mid 17th century for more than 100 years. Most Russian scholars agreed that Russian Zemsky Sobor was a Russian version of the estate-representative institution, trying to interpret Zemsky Sobor in a Western European model of political system. From our point of view, however, Russian Zemsky Sobor was quite different from feudal estate parliaments in both origin and function. It functioned only in the 16th-17th centuries for a short time and did not develop into a stable estate-representative institution, as it happened in Western Europe. In fact, the Zemsky Sobor institution has only expanded the class basis of the Tsarist regime and served merely as an instrument of the government in this period. When we try to interpret the evolution of Russian political system in the context of western models and concepts, what we could do is to tell what it appears to be, but what we could not do is tell what it is. [ABSTRACT FROM AUTHOR]