Title: Alexander I of Yugoslavia
Content:  Alexander I ( – 9 October 1934), also known as Alexander the Unifier,  was a prince regent of the Kingdom of Serbia from 1914 and later a king of Yugoslavia from 1921 to 1934 (prior to 1929 the state was known as the Kingdom of Serbs, Croats and Slovenes). He was assassinated by the Bulgarian Vlado Chernozemski, during a 1934 state visit to France.
Title: Alexander, Crown Prince of Yugoslavia
Content:  Alexander, Crown Prince of Yugoslavia, also claiming the crowned royal title of Alexander II Karađorđević ( / Aleksandar II Karađorđević; born 17 July 1945), is the head of the House of Karađorđević, the former royal house of the defunct Kingdom of Yugoslavia and its predecessor the Kingdom of Serbia. Alexander is the only child of King Peter II and his wife, Princess Alexandra of Greece and Denmark. He held the position of crown prince in the Democratic Federal Yugoslavia for the first four-and-a-half months of his life, from his birth until the declaration of the Federal People's Republic of Yugoslavia later in 1945. Born and raised in the United Kingdom, he enjoys close relationships with his relatives in the British royal family. His godparents were King George VI of the United Kingdom and his daughter, the then-Princess Elizabeth (now Queen Elizabeth II). Through his father Alexander is a direct descendant of Queen Victoria, through his great-great-grandfather Prince Alfred, Duke of Saxe-Coburg and Gotha, Victoria's second eldest son. Maternally he is also a direct descendant of Queen Victoria, through his great-great-grandmother Victoria, Empress of Germany, Victoria's eldest daughter. Alexander is known for his support of monarchism and his humanitarian work.
Title: Prince Alexander of Yugoslavia (1924–2016)
Content:  Prince Alexander of Yugoslavia (Александар П. Карађорђевић / Aleksandar P. Karađorđević; 13 August 1924 – 12 May 2016) was the elder son of Prince Paul, who served as Regent of Yugoslavia in the 1930s, and his wife, Princess Olga of Greece and Denmark.
Title: Kingdom of Yugoslavia
Content:  from 1903 (after the May Coup) onward. Peter I became the first king of Yugoslavia until his death in 1921. He was succeeded by his son Alexander I, who had been regent for his father. He was known as "Alexander the Unifier" and he renamed the kingdom "Yugoslavia" in 1929. He was assassinated in Marseille by Vlado Chernozemski, a member of the Internal Macedonian Revolutionary Organization (IMRO), during his visit to France in 1934. The crown passed to his 11-year-old son Peter. Alexander's cousin Paul ruled as Prince regent until 1941, when Peter II came of age. The royal family flew 
Title: Alexander I of Yugoslavia
Content:  Alexander Karađorđević was born on 16 December 1888 in the Principality of Montenegro as the fourth child (second son) of Peter Karađorđević (son of Prince Alexander of Serbia who thirty years earlier in 1858 was forced to abdicate and surrender power in Serbia to the rival House of Obrenović) and Princess Zorka of Montenegro (eldest daughter of Prince Nicholas of Montenegro). Despite enjoying support from the Russian Empire, at the time of Alexander's birth and early childhood, the House of Karađorđević was in political exile, with family members scattered all over Europe, unable to return to Serbia. Serbia had recently been transformed from a principality into a kingdom under the Obrenovićs, who 
Title: Alexander I of Yugoslavia
Content:  this Alexander bested Colonel Dragutin Dimitrijević "Apis" and in the wake of this Alexander's father, King Peter, agreed to hand over royal powers to his son. Though Colonel Dimitrijević was the mastermind of the 1903 coup that had restored the House of Karađorđević to the Serbian throne, Alexander distrusted him, regarding his attempts to set himself up as a "kingmaker" and to have the Serbian Army be a "state within the state" existing outside of civilian control as a major threat. Additionally, Alexander saw Dimitrijević as an irresponsible intriguer who having betrayed one king might always betray another. In January 1914, the Serbian 
Title: Alexander, Crown Prince of Yugoslavia
Content:  Alexander first came to Yugoslavia in 1991. He actively worked with the opposition to Slobodan Milošević and moved to Yugoslavia after Milošević had been deposed in 2000. On 27 February 2001, the parliament of the Federal Republic of Yugoslavia (FRY) passed legislation conferring citizenship on members of the Karađorđević family. The legislation may also have effectively annulled a decree stripping the family of its citizenship of the Socialist Federal Republic of Yugoslavia (SFRY) in 1947. The annulment was the topic of some debate. Notably, the FRY was not the successor of the SFRY; rather the FRY was a new state (and was admitted to the United Nations as a new state on that basis). Therefore, the jurisdiction of 
Title: Prince Andrew of Yugoslavia
Content:  Prince Andrew of Yugoslavia (28 June 1929 – 7 May 1990) was the youngest child of King Alexander I of Yugoslavia (1888–1934) and Maria of Yugoslavia (1900–1961). His paternal grandparents were King Peter I of Serbia (1844–1921) and Princess Zorka of Montenegro (1864–1890), while his maternal grandparents were King Ferdinand of Romania (1865–1927) and Princess Marie of Edinburgh (1875–1938).
Title: Alexander I of Yugoslavia
Content:  with strong support from Austria-Hungary. The antagonism between the two rival royal houses was such that after the assassination of Prince Mihailo Obrenović in 1868 (an event Karađorđevićs were suspected of taking part in), the Obrenovićs resorted to making constitutional changes, specifically proclaiming the Karađorđevićs banned from entering Serbia and stripping them of their civic rights. Alexander was two when his mother Princess Zorka died in 1890 from complications while giving birth to his younger brother Andrija, who died 23 days later. Alexander spent his childhood in Montenegro. In 1894 his widower father took the four children, including Alexander, to Geneva where the young man completed his elementary education. Alongside his 
Title: Prince Alexander of Yugoslavia (born 1982)
Content:  Prince Alexander of Yugoslavia, also known as Alexander III Karađorđević ( / Aleksandar III Karađorđević; born January 15, 1982), is a member of the House of Karađorđević.

Question: Who is the father of Alexander I of Yugoslavia?
Answer: Peter I of Serbia.