Concert of Europe in the context of "Quirinal Palace"

The Crimean War was fought between the Russian Empire and an alliance of the Ottoman Empire, the Second French Empire, the United Kingdom of Great Britain and Ireland, and the Kingdom of Sardinia-Piedmont from October 1853 to February 1856. Geopolitical causes of the war included the "Eastern question" (the decline of the Ottoman Empire), expansion of Imperial Russia in the preceding Russo-Turkish wars, and the British and French preference to preserve the Ottoman Empire to maintain the balance of power in the Concert of Europe.

The war's proximate cause was a dispute between France and Russia over the rights of Catholic and Orthodox minorities in Palestine. After the Sublime Porte refused Tsar Nicholas I's demand that the Empire's Orthodox subjects be placed under his protection, Russian troops occupied the Danubian Principalities in July 1853. The Ottomans declared war on Russia in October. Fearing the growth of Russian influence and compelled by public outrage over the annihilation of the Ottoman squadron at Sinop, Britain and France joined the war on the Ottoman side in March 1854. The Russian advance was halted at Silistria in June.

Mehmed Emin Âlî Pasha, also spelled as Mehmed Emin Aali (5 March 1815 – 7 September 1871), commonly known as Ali Pasha, was a Turkish–Ottoman statesman during the Tanzimat period, best known as the architect of the Ottoman Reform Edict of 1856, and for his role in the Treaty of Paris (1856) that ended the Crimean War. From humble origins as the son of a doorkeeper, Âli Pasha rose through the ranks of the Ottoman state and became the Minister of Foreign Affairs for a short time in 1840, and again in 1846. He became Grand Vizier for a few months in 1852. Between 1855 and 1871 he alternated between the two jobs, ultimately holding the position of Foreign Minister seven times and Grand Vizier five times in his lifetime. Âli Pasha was widely regarded as a deft and able statesman, and often credited with preventing an early break-up of the empire.

Âli Pasha advocated for a western style of reform to modernize the empire, including secularization of the state and education and improvements to civil liberties. He advocated for an Ottoman nationalism that would replace diverse ethnic and religious loyalties. To that end, non-Muslims started to serve in government, with a couple becoming cabinet ministers. In foreign policy, following the Crimean War the Ottoman Empire joined the Concert of Europe. Troops were withdrawn from Serbia, and the Cretan revolt was suppressed. His egalitarian reforms, dealings with Christian powers, and increasingly authoritarian regime were not without controversy, opponents of which coalesced around the Young Ottomans. After his death in 1871, a period of chaos resulted as reactionaries took control over the government, leading to the Great Eastern Crisis.

In diplomatic history, the Eastern question was the issue of the political and economic instability in the Ottoman Empire from the late 18th to early 20th centuries and the subsequent strategic competition and political considerations of the European great powers in light of this. Characterized as the "sick man of Europe", the relative weakening of the empire's military strength in the second half of the nineteenth century threatened to undermine the fragile balance of power system largely shaped by the Concert of Europe. The Eastern question encompassed myriad interrelated elements: Ottoman military defeats, Ottoman institutional insolvency, the ongoing Ottoman political and economic modernization programme, the rise of ethno-religious nationalism in its provinces, and Great Power rivalries. In an attempt to triangulate between these various concerns, the historian Leslie Rogne Schumacher has proposed the following definition of the Eastern Question:

The period in which the Eastern Question was internationally prominent is also open to interpretation. While there is no specific date on which the Eastern question began, the Russo-Turkish War of 1828–1829 brought the issue to the attention of the European powers, Russia and Britain in particular. As the dissolution of the Ottoman Empire was believed to be imminent, the European powers engaged in a power struggle to safeguard their military, strategic and commercial interests in the Ottoman domains. Imperial Russia stood to benefit from the decline of the Ottoman Empire; on the other hand, Austria-Hungary and United Kingdom deemed the preservation of the Empire to be in their best interests. The Eastern question was put to rest after the First World War, one of the outcomes of which was the collapse and division of the Ottoman holdings.

The Danubian Principalities (German: Donaufürstentümer, Russian: Дунайские княжества, Romanian: Principatele Dunărene) was a geopolitical term used for the Ottoman vassal principalities of Moldavia and Wallachia in the period of 1774–1858, a time of when the territories were a battleground between the Ottoman Empire, Habsburg Monarchy, and Russian Empire. While Russia returned Moldavia and Wallachia to the Ottoman Empire with the Treaty of Küçük Kaynarca (1774), it retained protectorship over the two and also of the Orthodox subjects in all of the Ottoman Empire. This made the two principalities have the status of dual authority, under Ottoman suzerainty but with Russian protection. The Russo-Turkish War (1828–1829) ended with the Russian occupation of the two principalities. The negotiations of the Great Powers in the aftermath of Russian defeat resulted in the unification of Moldavia and Wallachia in 1859.

Splendid isolation is a term used to describe the 19th-century British diplomatic practice of avoiding permanent alliances from 1815 to 1902. The concept developed as early as 1822, when Britain left the post-1815 Concert of Europe, and continued until the 1902 Anglo-Japanese Alliance and the 1904 Entente Cordiale with France. As Europe was divided into two power blocs, Britain became aligned with the French Third Republic and the Russian Empire (known as the Triple Entente) against the German Empire, Austria-Hungary and the Kingdom of Italy (The Triple Alliance).

The term was coined in January 1896 by a Canadian politician, George Eulas Foster. He indicated his approval for Britain's minimal involvement in European affairs by saying "In these somewhat troublesome days when the great Mother Empire stands splendidly isolated in Europe."

The Treaty of London of 1839, was signed on 19 April 1839 between the major European powers, the United Kingdom of the Netherlands, and the Kingdom of Belgium. It was a direct follow-up to the 1831 Treaty of the XVIII Articles, which the Netherlands had refused to sign, and the result of negotiations at the London Conference of 1838–1839 which sought to maintain the Concert of Europe.

Under the treaty, the European powers recognised and guaranteed the independence and neutrality of Belgium and established the full independence of the German-speaking part of Luxembourg. Article VII required Belgium to remain perpetually neutral. Following the German invasion of 1914, Belgium abandoned its policy of neutrality (except for a brief, unsuccessful resumption from 1936 to 1940).