M: emerged as Novgorod principality ruled by Rurik who further extended his power to Kievan Rus in the area populated by East Slavic and local Finno-Ugric tribes
splitting off from one existing country (marked by S in the table), or
through the merging of several existing countries (M).
A special case of a split-off is when a federal country dissolves by dividing up into its constituent states (D).
The date of independence of a country is often arguable; independence cannot be defined precisely. Also, whether something is a newly founded country, or whether it is the same as a previously existing one, is often arguable. In general, if a new political entity has mostly the same area as one of its predecessors, it will be considered as the same country as the predecessor.
Times of temporary dependence may present problems. If the dependence on another country is short and the country survives it without major changes in its area and constitution, such as a period of occupation during a war, it will be ignored. Otherwise, the country will be considered a new creation.
This list presents an attempt to give a simple view of a certain aspect of European history. Oversimplifications are unavoidable.
