King Alexander I of Yugoslavia, who was regent of Serbia between 1914 and 1934, was a decisive figure in the political life of the Balkans at the time. He was born on December 16, 1888 in Cetinje, Montenegro, and died on October 9, 1934 in Marseille, France. At the outbreak of the First World War, on July 5, 1914, he took over the duties of regency in place of his ailing father, King Peter I . During the war, he was the commander of the Serbian army, but due to the occupation of the central powers, he lived in exile in Greece together with the royal family and the government from November 1915 to December 1918. In 1921, after the death of his father, he became the king of Yugoslavia. During his reign, he made several significant changes, including the royal dictatorship introduced on October 3, 1929, during which he changed the country's name from the Kingdom of Serbs, Croats and Slovenes to Yugoslavia.I. Under Alexander's royal dictatorship, internal political tensions increased, and these tensions eventually led to tragedy. On October 9, 1934, he was assassinated in Marseille by a Macedonian nationalist, Vlado Chernozemski.I. Sándor married the Romanian Royal Princess Mária of Hohenzollern-Sigmaringen, and they had three sons: Péter, Tomiszláv and András. His reign and life form an important part of the House of Karađorđević and Yugoslav and Serbian history.

The coinage of Alexander I, king of Yugoslavia from 1921-1934 and regent of Serbia from 1914-1921, was as follows: in 1920, the Yugoslav crown replaced the Serbian dinar, which was introduced by Alexander as regent during World War I. The Yugoslav crown was gold-backed and a member of the Latin Monetary Union. The coins of the crown bore the portrait of Alexander and the name of the Kingdom of Serbs-Croatians-Slovenes was written on them. In 1925, the Yugoslav crown was replaced by the Yugoslav dinar, the value of which was 1:1 to the crown. The dinar coins also bore Alexander's portrait, but the name of the Kingdom of Yugoslavia, which was introduced in 1929, was written on it. The dinar coins were made of a variety of materials, such as silver, nickel, aluminum, and bronze. In 1931, the Yugoslav dinar devalued to 56.4 dinars to the British pound. After the devaluation, new coins were minted that were smaller and contained less precious metal. In addition to the coins bearing the portrait of Alexander I, there were also coins with coats of arms depicting the symbol of the Yugoslav state. In 1934, Alexander was the victim of an assassination attempt in Marseille, and his son, II. Peter inherited the throne. In addition to the portrait of the king, the date of his death was also included on the coins minted in his memory. II. Coins minted under Peter show the portrait of the young king, who was 11 years old when his father died.