Elizabeth of Luxembourg (; 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. She could not completely assert her position though, because the Veszprém bishop refused to give up on his right to crown the queen (the monarch was traditionally crowned by the Esztergom bishop). She was however recognized as co-ruler and played an active part in the government. After Albert's death though, she was unable to prevent the election of a new king. Albert died in 1439, leaving Elizabeth a pregnant dowager with two daughters, Anne and Elizabeth. Bohemian nobility proclaimed an interregnum, while King Vladislaus III of Poland was crowned new king of Hungary in May 1440, three months after Queen Elizabeth delivered a son, Ladislaus the Posthumous. She was determined to contend for her patrimony on her son's behalf, which led to a civil war between hers and Vladislaus's supporters. The conflict ended with the queen's death at the age of 33. Birth Her real birth date can be calculated by virtue of a letter of King Sigismund to Kéméndi Péter fia János (John, son of Peter Kemendi), Lord-lieutenant of Zala County dated 26 April 1410 (sabbato post festum s. Georgii) at Végles, Kingdom of Hungary (now Vígľaš, Slovakia) and sealed with Queen Barbara's seal, who also stayed there and in which the king informs him about his daughter's birth alias circa festum beati Francisci confessoris. Because this feast falls on 4 October, it must have happened in the previous year, that is, 1409 and in October. Baranyai (1926) argues that the usage of circa can allow some variations towards September but if it had occurred in September, he would have referred to the feast of Saint Michael which falls on 29 September instead of that of Francis of Assisi. The only remaining question, namely the exact day is educed from the engagement date of his daughter to Archduke Albert which was held on 7 October 1411, Pozsony, Kingdom of Hungary (now Bratislava, Slovakia, Pressburg in German) and probably may have adjusted to a former important event because it belongs to no