Gathering of the Russian lands

The gathering of the Russian lands or Rus' lands (Russian: собирание русских земель) was the process in which new states – usually the Principality of Moscow and the Grand Duchy of Lithuania – acquired former territories of Kievan Rus' from the 14th century onwards, claiming to be its legitimate successor. In Russian historiography, this phenomenon represented the consolidation of a national state centered on Moscow. The sobriquet gatherer of the Russian lands or Rus' Land (Russian: собиратель русской земли, romanized: sobiratel' russkoi zemli) is also given to the grand princes of Moscow by Russian historians, especially to Ivan III. The term is also used to describe the expansion of the Grand Duchy of Lithuania into Rus' principalities; the Lithuanian grand dukes claimed authority over all territories inhabited by Rus' people (East Slavs). Some historians argue that Lithuania began "gathering Rus' lands" before Muscovy did. The rules of Moscow adopted the title Sovereign of all Russia (later changed to Tsar of all Russia and finally Emperor and Autocrat of all Russia) while the Lithuanian Grand Dukes adopted the title King of the Lithuanians and [many] Ruthenians and later under the Polish–Lithuanian union as King of Poland, Grand Prince of Lithuania, Rus', Prussia, Samogitia, Mazovia and other.