Filiki Eteria or Society of Friends was a secret political and revolutionary organization founded in 1814 in Odessa, whose purpose was to overthrow the Ottoman rule of Greece and establish an independent Greek State. Society members were mainly young Phanariot Greeks from Constantinople and the Russian Empire, local political and military leaders from the Greek mainland and islands, as well as several Orthodox Christian leaders from other nations that were under Hellenic influence, such as Karađorđe from Serbia, and Tudor Vladimirescu from Romania. One of its leaders was the prominent Phanariote Prince Alexander Ypsilantis. The Society initiated the Greek War of Independence in the spring of 1821.

The Danubian Principalities was a conventional name given to the Principalities of Moldavia and Wallachia, which emerged in the early 14th century. The term was coined in the Habsburg monarchy after the Treaty of Küçük Kaynarca (1774) in order to designate an area on the lower Danube with a common geopolitical situation. The term was largely used then by foreign political circles and public opinion until the union of the two principalities in 1859. Alongside Transylvania, the United Principalities of Moldavia and Wallachia became the basis for the Kingdom of Romania, and by extension the modern nation-state of Romania.