Peter I of Serbia in the context of "Alexander I of Yugoslavia"

Yugoslavia (/ˌjuːɡoʊˈslɑːviə/; lit. 'Land of the South Slavs') was a country in Central Europe and the Balkans that existed from 1918 to 2003. It came into existence following World War I, under the name of the Kingdom of Serbs, Croats and Slovenes, from the merger of the Kingdom of Serbia with the provisional State of Slovenes, Croats and Serbs, and constituted the first union of South Slavic peoples as a sovereign state, following centuries of foreign rule over the region under the Ottoman Empire and the Habsburg monarchy.

Under the rule of the House of Karađorđević, the kingdom gained international recognition on 13 July 1922 at the Conference of Ambassadors in Paris and was renamed the Kingdom of Yugoslavia on 3 October 1929. Peter I was the country's first sovereign. Upon his father's death in 1921, Alexander I went on to rule the country through an extended period of political crisis that culminated in the 6 January Dictatorship and, ultimately, his assassination in 1934. Prince Paul headed the state as a prince regent until Alexander's son Peter II was declared of-age, which happened following the Yugoslav coup d'état in March 1941. Alexander I was the longest reigning of the three Yugoslav monarchs.

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.

The 1920s (pronounced "nineteen-twenties" often shortened to the "'20s" or the "Twenties") was a decade that began on January 1, 1920, and ended on December 31, 1929. Primarily known for the economic boom that occurred in the Western World following the end of World War I (1914–1918), the decade is frequently referred to as the "Roaring Twenties" or the "Jazz Age" in America and Western Europe, and the "Golden Twenties" in Germany, while French speakers refer to the period as the "Années folles" ('crazy years') to emphasize the decade's social, artistic, and cultural dynamism.

The devastating Wall Street crash in October 1929 is generally viewed as a harbinger of the end of 1920s prosperity in North America and Europe. In the Soviet Union, the New Economic Policy was created by the Bolsheviks in 1921, to be replaced by the first five-year plan in 1928. The 1920s saw the rise of radical political movements, with the Red Army triumphing against White movement forces in the Russian Civil War, and the emergence of far-right political movements in Europe. In 1922, the fascist leader Benito Mussolini seized power in Italy. Other dictators that emerged included Józef Piłsudski in Poland, and Peter and Alexander Karađorđević in Yugoslavia. First-wave feminism made advances, with women gaining the right to vote in the United States (1920), Albania (1920), Ireland (1921), and with suffrage being expanded in Britain to all women over 21 years old (1928).

Princess Zorka Karađorđević (Serbian Cyrillic: Кнегиња црногорска Зорка; 23 December [O.S. 11 December] 1864 – 16 March [O.S. 4 March] 1890), born Princess Ljubica of Montenegro, was the eldest child of Prince Nicholas I and Princess Milena of Montenegro, who later became the country's king and queen consort. In 1883, Ljubica married Prince Peter Karađorđević and she changed her name to Zorka (and her surname to Karađorđević). She died in childbirth while giving birth to Prince Andrija on 16 March 1890. Prince Andrija died shortly thereafter. Zorka's husband later became king of Serbia as Peter I.

Persida Karađorđević née Nenadović (Serbian Cyrillic: Персида Ненадовић; 15 February 1813 – 29 March 1873) was the Princess of Serbia as the wife of Alexander Karađorđević, who ruled the Principality of Serbia from his election on 14 September 1842 until his abdication on 24 October 1858. She was the mother of ten children, including future king Peter I of Serbia, who succeeded to the throne after the assassination of King Alexander I, the last ruler of the Obrenović dynasty (the traditional rivals of the Karađorđevićs).

Ermine (/ˈɜːrmɪn/) in heraldry is a fur, a type of tincture, consisting of a white background with a pattern of black shapes representing the winter coat of the stoat (a species of weasel with white fur and a black-tipped tail). The linings of medieval coronation cloaks and some other garments, usually reserved for use by high-ranking peers and royalty, were made by sewing many ermine furs together to produce a luxurious white fur with patterns of hanging black-tipped tails. Due largely to the association of the ermine fur with the linings of coronation cloaks, crowns and peerage caps, the heraldic tincture of ermine was usually reserved to similar applications in heraldry (i.e., the linings of crowns and chapeaux and of the royal canopy). In heraldry it has become especially associated with the Duchy of Brittany and Breton heraldry.