Grand Duchy of Lithuania

State · 1220–1449 CE · at its largest around 1375 CE

Baltic state united by Mindaugas that expanded into the lands of Rus' to become one of Europe's largest states, entering a union with Poland in 1386.

On its lands while it lasted

Jelgava (1226 CE): Capital of Duchy of Courland (1734–1793).
Kosice (1230 CE): Capital of Principality of Upper Hungary (1683–1685).
Mongol invasion of Kievan Rus' (1237–1242 CE): Mongol armies under Batu Khan destroyed Ryazan, Vladimir and Kyiv, subjecting the Rus' principalities to Mongol overlordship for over two centuries.
Klaipeda (1252 CE): Capital of Kingdom of Prussia (1707–1708).
Kernave (c. 1279 CE): Capital of Grand Duchy of Lithuania (1279–1321).
Trakai (c. 1321 CE): Capital of Grand Duchy of Lithuania (1321–1323).
Siret (1326 CE): Capital of Principality of Moldavia (1363–1388).
Union of Krewo (1385 CE): Agreement for Grand Duke Jogaila of Lithuania to marry Queen Jadwiga of Poland, uniting the two states and leading to Lithuania's conversion to Christianity.
Suceava (1388 CE): Capital of Principality of Moldavia (1388–1564).
Iasi (1408 CE): Capital of Principality of Moldavia (1564–1858), United Principalities of Moldavia and Wallachia (1859–1862).
Rublev’s Trinity (c. 1425 CE): Andrei Rublev painted the three angels who visited Abraham as an image of the Trinity, for the Trinity Lavra of St Sergius near Moscow. It is the most celebrated of all Russian icons.
Chisinau (1436 CE): Capital of Republic of Moldova (1992–today).
Ivan III (1440 CE – 1505 CE): Grand Prince of Moscow who gathered the Russian lands, annexed Novgorod and ended the Golden Horde's overlordship.