Old Style and New Style dates in the context of Mikhail Bulgakov

Swan Lake (Russian: Лебеди́ное о́зеро, romanized: Lebedínoje ózero, Russian pronunciation: [lʲɪbʲɪˈdʲinəjə ˈozʲɪrə]), Opus 20, is a ballet composed by Pyotr Ilyich Tchaikovsky between 1875 and 1876. The original production premiered at the Bolshoi Theatre in Moscow on 4 March 1877 (20 February Old Style), with choreography by Julius Reisinger. The ballet, initially conceived in two acts, is based on Russian and German folk tales and tells the story of Princess Odette, who is transformed into a swan by the sorcerer Von Rothbart.

The initial reception was lukewarm, with criticism directed at various elements of the production. Despite this, Swan Lake has become one of the most frequently performed ballets worldwide.

Don Quixote is a ballet in three acts, based on episodes taken from the famous novel Don Quixote de la Mancha by Miguel de Cervantes. It was originally choreographed by Marius Petipa to the music of Ludwig Minkus and first presented by Moscow's Bolshoi Ballet on 26 December [O.S. 14 December] 1869. Petipa and Minkus revised the ballet into a more elaborate and expansive version in five acts and eleven scenes for the Mariinsky Ballet, first presented on 21 November [O.S. 9 November] 1871 at the Imperial Bolshoi Kamenny Theatre of St. Petersburg.

All modern productions of the Petipa/Minkus ballet are derived from the version staged by Alexander Gorsky for the Bolshoi Theatre of Moscow in 1900, a production the ballet master staged for the Imperial Ballet of St. Petersburg in 1902.

Sir Isaac Newton (/ˈnjuːtən/ ; 4 January [O.S. 25 December] 1643 – 31 March [O.S. 20 March] 1727) was an English polymath active as a mathematician, physicist, astronomer, alchemist, theologian, author, and inventor. He was a key figure in the Scientific Revolution and the Enlightenment that followed. His book Philosophiæ Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy), first published in 1687, achieved the first great unification in physics and established classical mechanics. Newton also made seminal contributions to optics, and shares credit with German mathematician Gottfried Wilhelm Leibniz for formulating infinitesimal calculus, though he developed calculus years before Leibniz. Newton contributed to and refined the scientific method, and his work is considered the most influential in bringing forth modern science.

In the Principia, Newton formulated the laws of motion and universal gravitation that formed the dominant scientific viewpoint for centuries until it was superseded by the theory of relativity. He used his mathematical description of gravity to derive Kepler's laws of planetary motion, account for tides, the trajectories of comets, the precession of the equinoxes and other phenomena, eradicating doubt about the Solar System's heliocentricity. Newton solved the two-body problem and introduced the three-body problem. He demonstrated that the motion of objects on Earth and celestial bodies could be accounted for by the same principles. Newton's inference that the Earth is an oblate spheroid was later confirmed by the geodetic measurements of Alexis Clairaut, Charles Marie de La Condamine, and others, convincing most European scientists of the superiority of Newtonian mechanics over earlier systems. He was also the first to calculate the age of Earth by experiment, and described a precursor to the modern wind tunnel. Further, he was the first to provide a quantitative estimate of the solar mass.

John Locke (/lɒk/; 29 August 1632 (O.S.) – 28 October 1704 (O.S.)) was an English philosopher and physician, widely regarded as one of the most influential of the Enlightenment thinkers and commonly known as the "father of liberalism". Considered one of the first of the British empiricists, following the tradition of Francis Bacon, Locke is equally important to social contract theory. His work greatly affected the development of epistemology and political philosophy.

His writings influenced Voltaire, Jean-Jacques Rousseau, and many Scottish Enlightenment thinkers, as well as the American Revolutionaries. His contributions to classical republicanism and liberal theory are reflected in the United States Declaration of Independence. Internationally, Locke's political-legal principles continue to have a profound influence on the theory and practice of limited representative government and the protection of basic rights and freedoms under the rule of law.

The Russian Empire formally annexed the Crimean Khanate on 19 April [O.S. 8 April] 1783, following a decade-long campaign of intervention in the Crimean Peninsula. Russia aimed to control the Black Sea and end raids by Crimean slavers into its territory. To accomplish this, the Russians waged a series of wars against the Ottoman Empire and its Crimean vassal state, culminating in victory in the 1768–1774 Russo-Turkish War. The Treaty of Küçük Kaynarca, signed in 1774, granted the Crimean Khanate nominal independence from the Ottomans under Russian influence. In subsequent years, Russia would intervene widely in Crimean affairs, provoking a series of revolts by the Crimean Tatars, while the Ottomans watched in ambivalence. Crimea was finally annexed by Russia on 19 April 1783, after Russian imperial advisor Prince Grigory Potemkin encouraged Empress Catherine the Great to dissolve the khanate and formally claim its territory. The annexation ended the centuries-long Crimean slave trade. Under Russian administration, the former khanate was subjected to a long-term policy of de-Tatarisation. Tatar property was confiscated, and Russians were encouraged to settle in the region, sparking waves of Tatar emigration.

The Russian Revolution was a period of political and social change in Russia, starting in 1917. This period saw Russia abolish its monarchy and adopt a socialist form of government following two successive revolutions and a civil war. It can be seen as the precursor for other revolutions that occurred in the aftermath of World War I, such as the German Revolution of 1918–1919. The Russian Revolution was a key event of the 20th century.

The Russian Revolution was inaugurated with the February Revolution in 1917, in the midst of World War I. With the German Empire inflicting defeats on the front, and increasing logistical problems causing shortages of bread and grain, the Russian Army was losing morale, with large scale mutiny looming. Officials were convinced that if Tsar Nicholas II abdicated, the unrest would subside. Nicholas stepped down on 15 March [O.S. 2 March], ushering in a provisional government led by the Duma (parliament). During the unrest, Soviet councils were formed by locals in Petrograd (now Saint Petersburg) that initially did not oppose the new government; however, the Soviets insisted on their influence in the government and control over militias. By March, Russia had two rival governments. The Provisional Government held state power in military and international affairs, whereas the network of Soviets held domestic power. Critically, the Soviets held the allegiance of the working class, and urban middle class. There were mutinies, protests and strikes. Socialist and other leftist political organizations competed for influence within the Provisional Government and Soviets. Factions included the Mensheviks, Social Revolutionaries, Anarchists, and the Bolsheviks, a far-left party led by Vladimir Lenin.

The Russian Soviet Federative Socialist Republic (Russian SFSR), previously known as the Russian Socialist Federative Soviet Republic (RSFSR) and the Russian Soviet Republic, and unofficially as Soviet Russia, was a socialist state from 1917 to 1922, and afterwards the largest and most populous constituent republic of the Soviet Union (USSR) from 1922 to 1991, until becoming a sovereign part of the Soviet Union with priority of Russian laws over Union-level legislation in 1990 and 1991, the last two years of the existence of the USSR. The Russian SFSR was composed of sixteen smaller constituent units of autonomous republics, five autonomous oblasts, ten autonomous okrugs, six krais and forty oblasts. Russians formed the largest ethnic group. The capital of the Russian SFSR and the USSR as a whole was Moscow and the other major urban centers included Leningrad (Petrograd until 1924), Stalingrad (Volgograd after 1961), Novosibirsk, Sverdlovsk, Gorky and Kuybyshev.

On 7 November 1917 [O.S. 25 October], as a result of the October Revolution, the Russian Soviet Republic was proclaimed as a sovereign state and the world's first constitutionally socialist state guided by communist ideology. The first constitution was adopted in 1918. In 1922, the Russian SFSR signed a treaty officially creating the USSR. On 12 June 1990, the Congress of People's Deputies adopted the Declaration of State Sovereignty. On 12 June 1991, Boris Yeltsin, supported by the Democratic Russia pro-reform movement, was elected the first and only President of the RSFSR, a post that would later become the Presidency of the Russian Federation. The August 1991 Soviet coup d'état attempt in Moscow with the temporary brief internment of President Mikhail Gorbachev destabilised the Soviet Union. Following these events, Gorbachev lost all his remaining power, with Yeltsin superseding him as the pre-eminent figure in the country. On 8 December 1991, the heads of Russia, Ukraine and Belarus signed the Belovezha Accords declaring dissolution of the USSR and established the Commonwealth of Independent States (CIS) as a loose replacement confederation. On 12 December, the agreement was ratified by the Supreme Soviet (the parliament of the Russian SFSR); therefore the Russian SFSR had renounced the Treaty on the Creation of the USSR and de facto declared Russia's independence from the USSR itself and the ties with the other Soviet republics.

Joseph Vissarionovich Stalin (né Dzhugashvili; 18 December [O.S. 6 December] 1878 – 5 March 1953) was a Soviet politician, dictator and revolutionary who led the Soviet Union from 1924 until his death in 1953. His rule oversaw mass atrocities that caused an estimated 20 million deaths, and he is widely considered one of the most brutal despots of the modern era. He held office as General Secretary of the Communist Party from 1922 to 1952 and as premier from 1941 until his death. Despite initially governing the country as part of a collective leadership, he eventually consolidated power to become a dictator by the 1930s. Stalin codified the party's official interpretation of Marxism as Marxism–Leninism, and his version of it is referred to as Stalinism.

Born into a poor Georgian family in Gori, Russian Empire, Stalin attended the Tiflis Theological Seminary before joining the Marxist Russian Social Democratic Labour Party. He raised funds for Vladimir Lenin's Bolshevik faction through bank robberies and other crimes, and edited the party's newspaper, Pravda. He was repeatedly arrested and underwent several exiles to Siberia. After the Bolsheviks seized power in the October Revolution of 1917, Stalin served as a member of the Politburo, and from 1922 used his position as General Secretary to gain control over the party bureaucracy. After Lenin's death in 1924, Stalin won the leadership struggle over rivals including Leon Trotsky. Stalin's doctrine of socialism in one country became central to the party's ideology, and his five-year plans starting in 1928 led to forced agricultural collectivisation, rapid industrialisation, and a centralised command economy. His policies contributed to a famine in 1932–1933 which killed millions, including in the Holodomor in Ukraine. Between 1936 and 1938, Stalin executed hundreds of thousands of his real and perceived political opponents in the Great Purge. Under his regime, an estimated 18 million people passed through the Gulag system of forced labour camps, and more than six million people, including kulaks and entire ethnic groups, were deported to remote areas of the country.

Aleksey Petrovich Pavlov (Russian: Алексей Петрович Павлов; 1 December [O.S. 19 November] 1854 – 9 September 1929) was a Russian Imperial geologist and paleontologist, who made a significant contribution in the field of stratigraphy. He was professor at Moscow Imperial University and an academician of the St. Petersburg Imperial Academy of Sciences. He published more than 160 works, especially in the fields of stratigraphy and paleontology.

He was married to Maria Vasilievna (nee Gortynskaya) Pavlova who is noted for her work as a paleontologist and academician. The Museum of Paleontology at Moscow State University is named to honor them jointly for their contributions to the field.

Viktor Mikhaylovich Vasnetsov (Russian: Ви́ктор Миха́йлович Васнецо́в; 15 May [O.S. 3 May] 1848 – 23 July 1926) was a Russian painter and draughtsman who specialised in mythological and historical subjects. He is considered a co-founder of Russian folklorist and romantic nationalistic painting, and a key figure in the Russian Revivalist movement.

The Tsardom of Bulgaria (Bulgarian: Царство България, romanized: Tsarstvo Bŭlgariya), also known as the Third Bulgarian Tsardom (Bulgarian: Трето Българско Царство, romanized: Treto Bŭlgarsko Tsarstvo), usually known in English as the Kingdom of Bulgaria, or simply Bulgaria, was a constitutional monarchy in Southeastern Europe, which was established on 5 October [O.S. 22 September] 1908, when the Bulgarian state was raised from a principality to a tsardom.

Prince Ferdinand, founder of the royal family, was crowned as tsar at the Declaration of Independence, mainly because of his military plans and for seeking options for unification of all lands in the Balkans region with an ethnic Bulgarian majority (lands that had been seized from Bulgaria and given to the Ottoman Empire in the Treaty of Berlin). He and his successors were reckoned as kings internationally.

The Kingdom of Romania (Romanian: Regatul României) was a constitutional monarchy that existed from 25 March [O.S. 13 March] 1881 with the crowning of prince Karl of Hohenzollern-Sigmaringen as King Carol I (thus beginning the Romanian royal family), until 1947 with the abdication of King Michael I and the Romanian parliament's proclamation of the Romanian People's Republic.

From 1859 to 1877, Romania evolved from a personal union of two principalities: (Moldavia and Wallachia) called the Unification of Moldavia and Wallachia also known as "The Little Union" under a single prince to an autonomous principality with a Hohenzollern monarchy. The country gained its independence from the Ottoman Empire during the 1877–1878 Russo-Turkish War (known locally as the Romanian War of Independence), after which it was forced to cede the southern part of Bessarabia in exchange for Northern Dobruja. The kingdom's territory during the reign of King Carol I, between 13 (O.S.) / 25 March 1881 and 27 September (O.S.) / 10 October 1914 is sometimes referred to as the Romanian Old Kingdom, to distinguish it from "Greater Romania", which included the provinces that became part of the state after World War I (Bessarabia, Banat, Bukovina, and Transylvania).

The May Coup (Serbian: Мајски преврат, romanized: Majski prevrat) was a coup d'état in the Kingdom of Serbia which resulted in the assassination of King Alexander I and his consort, Queen Draga, inside the Stari Dvor in Belgrade on the night of 10–11 June [O.S. 28–29 May] 1903. This act resulted in the extinction of the Obrenović dynasty that had ruled Serbia since the middle of the 19th century. A group of army officers led by Captain Dragutin Dimitrijević (Apis) organized the assassination. After the May Coup, the throne passed to King Peter I of the Karađorđević dynasty.

Along with the royal couple, the conspirators killed prime minister Dimitrije Cincar-Marković, minister of the army Milovan Pavlović [sr], and general-adjutant Lazar Petrović. The coup had a significant influence on Serbia's relations with other European powers; the Obrenović dynasty had mostly allied with Austria-Hungary, while the Karađorđević dynasty had close ties both with Russia and with France. Each dynasty received ongoing financial support from their powerful foreign sponsors.

Alexandru Ioan Cuza (Romanian: [alekˈsandru iˈo̯aŋ ˈkuza] , or Alexandru Ioan I, also Anglicised as Alexander John Cuza; 20 March [O.S. 8 March] 1820 – 15 May 1873) was the first domnitor (prince) of the Romanian Principalities through his double election as Prince of Moldavia on 5 January 1859 and Prince of Wallachia on 24 January 1859, which resulted in the unification of the two states. He was a prominent figure of the Moldavian Revolution of 1848. Following his double election, he initiated a series of liberal and progressive reforms that contributed to the modernization of Romanian society and of state structures.

As ruler of the Romanian Principalities, he supported a political and diplomatic activity for the recognition of the union of Moldavia and Wallachia by the suzerain Ottoman Empire and achieved constitutional and administrative unity between Moldavia and Wallachia in 1862, when the Romanian Principalities officially adopted the name Romanian United Principalities with a single capital at Bucharest, a single national assembly and a single government.

Carol I or Charles I of Romania (born Karl Eitel Friedrich Zephyrinus Ludwig von Hohenzollern-Sigmaringen; 20 April 1839 – 10 October [O.S. 27 September] 1914), nicknamed the King of Independence (Romanian: Regele Independenței), was the monarch of Romania from 1866 to his death in 1914, ruling as Prince (Domnitor) from 1866 to 1881, and as King from 1881 to 1914. He was elected Prince of the Romanian United Principalities on 20 April 1866 after the overthrow of Alexandru Ioan Cuza by a palace coup d'état. In May 1877, Romania was proclaimed an independent and sovereign nation. The defeat of the Ottoman Empire (1878) in the Russo-Turkish War secured Romanian independence, and he was proclaimed King on 26 March [O.S. 14 March] 1881. He was the first ruler of the Hohenzollern-Sigmaringen dynasty, which ruled the country until the proclamation of a socialist republic in 1947.

During his reign, Carol I personally led Romanian troops during the Russo-Turkish War and assumed command of the Russo-Romanian army during the siege of Plevna. The country achieved internationally recognized independence via the Treaty of Berlin, 1878 and acquired Southern Dobruja from Bulgaria in 1913. In 1883 the king entered a top-secret military alliance with the Austro-Hungarian Empire, despite popular demands against Hungary. When World War I broke out he was unable to activate the alliance. Romania remained neutral and in 1916 joined the Allies.

The Romanian War of Independence (Romanian: Războiul de Independență al României) is the name used in Romanian historiography to refer to the phase of the Russo-Turkish War (1877–78), in which Romania, fighting on the Russian side of the war, gained independence from the Ottoman Empire. On April 16 [O.S. April 4] 1877, Romania and the Russian Empire signed a treaty at Bucharest under which Russian troops were allowed to pass through Romanian territory, with the condition that Russia respected the integrity of Romania. Consequently, the mobilization of the Romanian troops also began, and around 114,000 soldiers were massed in the south of the country to defend against an eventual attack of the Ottoman forces from south of the Danube. On April 24 [O.S. April 12] 1877, Russia declared war on the Ottoman Empire and its troops entered Romania through the newly built Eiffel Bridge, on their way to the Ottoman Empire. Due to great losses, the Russian Empire asked Romania to intervene. On July 24 [O.S. July 12] 1877, the first Romanian Army units crossed the Danube and joined forces with the Russian Army.

Gottfried Wilhelm Leibniz (or Leibnitz; 1 July 1646 [O.S. 21 June] – 14 November 1716) was a German polymath active as a mathematician, philosopher, scientist and diplomat who is credited, alongside Isaac Newton, with the creation of calculus in addition to many other branches of mathematics, such as binary arithmetic and statistics. Leibniz has been called the "last universal genius" due to his vast expertise across fields, which became a rarity after his lifetime with the coming of the Industrial Revolution and the spread of specialized labour. He is a prominent figure in both the history of philosophy and the history of mathematics. He wrote works on philosophy, theology, ethics, politics, law, history, philology, games, music, and other studies. Leibniz also made major contributions to physics and technology, and anticipated notions that surfaced much later in probability theory, biology, medicine, geology, psychology, linguistics and computer science.

Leibniz contributed to the field of library science, developing a cataloguing system (at the Herzog August Library in Wolfenbüttel, Germany) that came to serve as a model for many of Europe's largest libraries. His contributions to a wide range of subjects were scattered in various learned journals, in tens of thousands of letters and in unpublished manuscripts. He wrote in several languages, primarily in Latin, French and German.

Samuel Johnson (18 September [O.S. 7 September] 1709 – 13 December 1784), often called Dr Johnson, was an English writer who made lasting contributions as a poet, playwright, essayist, moralist, literary critic, sermonist, biographer, editor, and lexicographer. The Oxford Dictionary of National Biography calls him "arguably the most distinguished man of letters in English history".

Born in Lichfield, Staffordshire, he attended Pembroke College, Oxford, until lack of funds forced him to leave. After working as a teacher, he moved to London and began writing for The Gentleman's Magazine. Early works include Life of Mr Richard Savage, the poems London and The Vanity of Human Wishes and the play Irene. After nine years' effort, Johnson's A Dictionary of the English Language appeared in 1755, and was acclaimed as "one of the greatest single achievements of scholarship". Later work included essays, an annotated The Plays of William Shakespeare, and the apologue The History of Rasselas, Prince of Abissinia. In 1763 he befriended James Boswell, with whom he travelled to Scotland, as Johnson described in A Journey to the Western Islands of Scotland. Near the end of his life came a massive, influential Lives of the Most Eminent English Poets of the 17th and 18th centuries.

Catherine II (born Princess Sophia Augusta Frederica, Russian: Екатерина Алексеевна Романова; 2 May 1729 – 17 November [O.S. 6 November] 1796), commonly known as Catherine the Great, was the reigning Empress of Russia from 1762 to 1796. She came to power after a coup d'etat against her husband, Peter III. Her long reign helped Russia thrive under a golden age under the Enlightenment. This renaissance led to the founding of many new cities, universities, and theatres, along with large-scale immigration from the rest of Europe and the recognition of Russia as one of the great powers of Europe.

After overthrowing and possibly assassinating her husband and her subsequent rule of the Russian Empire, Catherine often relied on noble favourites such as Count Grigory Orlov and Grigory Potemkin. Assisted by highly successful generals such as Alexander Suvorov and Pyotr Rumyantsev and admirals such as Samuel Greig and Fyodor Ushakov, she governed at a time when the Russian Empire was expanding rapidly by conquest and diplomacy. In the west, she installed her former lover to the throne of Poland, which was eventually partitioned. In the south, the Crimean Khanate was annexed following victories over the Bar Confederation and the Ottoman Empire in the Russo-Turkish War. With the support of Great Britain, Russia colonised the territories of New Russia along the coasts of the Black and Azov Seas. In the east, Russians became the first Europeans to colonise Alaska, establishing Russian America.

Mayflower was an English sailing ship that transported a group of English families, known today as the Pilgrims, from England to the New World in 1620. After 10 weeks at sea, Mayflower, with 102 passengers and a crew of about 30, reached what is today the United States, dropping anchor near the tip of Cape Cod, Massachusetts, on November 21 [O.S. November 11], 1620.

Differing from their contemporary Puritans (who sought to reform and purify the Church of England), the Pilgrims chose to separate themselves from the Church of England, which forced them to pray in private. They believed that its resistance to reform and Roman Catholic past left it beyond redemption. Starting in 1608, a group of English families left England for the Netherlands, where they could worship freely. By 1620, the community determined to cross the Atlantic for America, which they considered a "new Promised Land", where they would establish Plymouth Colony.