Elizabeth of Luxembourg (Hungarian: Luxemburgi Erzsébet; 7 October 1409 – 19 December 1442) was queen consort of Hungary, queen consort of Germany and Bohemia.
The only child of Holy Roman Emperor Sigismund, King of Hungary and Bohemia, Elizabeth was expected to ascend his thrones along with her husband, Albert of Austria. After her father's death, Elizabeth and her husband were elected by the Hungarian estates as de facto equal rulers.
Ladislaus V, more commonly known as Ladislaus the Posthumous (Hungarian: Utószülött László; Croatian: Ladislav Posmrtni; Czech: Ladislav Pohrobek; German: Ladislaus Postumus; 22 February 1440 – 23 November 1457), was Duke of Austria and King of Hungary, Croatia and Bohemia. He was the posthumous son of Albert of Habsburg with Elizabeth of Luxembourg. Albert had bequeathed all his realms to his future son on his deathbed, but only the estates of Austria accepted his last will. Fearing an Ottoman invasion, the majority of the Hungarian lords and prelates offered the crown to Vladislaus III of Poland. The Hussite noblemen and towns of Bohemia did not acknowledge the hereditary right of Albert's descendants to the throne, but also did not elect a new king.
After Ladislaus's birth, his mother seized the Holy Crown of Hungary and had Ladislaus crowned king in Székesfehérvár on 15 May 1440. However, the Diet of Hungary declared Ladislaus's coronation invalid and elected Vladislaus I as king. A civil war broke out which lasted for years. Elizabeth appointed her late husband's distant cousin, Albert VI as her child's guardian. However, as a representative of the interests of the Austrian and Hungarian estates, he could not defend himself against his older brother and rival, Frederick III, King of the Romans, who in turn took over his role as guardian of Ladislaus. Albert had to renounce his guardianship and in return received the mighty Hungarian border castle Forchtenstein, including a principality in the Hungarian-Styrian-Carinthian area. Ladislaus lived at Frederick's court (mainly in Wiener Neustadt), where Aeneas Silvius Piccolomini (later Pope Pius II) wrote a treatise on his upbringing.