Unification of Moldavia and Wallachia
The unification of Moldavia and Wallachia (Romanian: Unirea Moldovei și Țării Românești), also known as the unification of the Romanian Principalities (Romanian: Unirea Principatelor Române) or as the Little Union (Romanian: Mica Unire), happened on 1859 following the election of Alexandru Ioan Cuza as prince of both the Principality of Moldavia and the Principality of Wallachia. A possible joining between the two principalities, which shared a common Romanian ethnicity, language and culture, had been attempted to be avoided by the great powers for a long time, although it was allowed at the moment it happened.
It is celebrated every 24 January through the Day of the Unification of the Romanian Principalities in both Romania (officially) and Moldova (unofficially).