February 11, 1466 - February 11, 1503
Elizabeth was at the centre of one of the stickiest dynastic tangles England ever experienced. She was one of eleven children of Edward IV of England; you'd think that having 11 children would make a throne secure in a culture of inherited kingship. But this was not so, for a number of reasons: one, Edward died when his eldest son was still just a boy. Two, Edward's own claim to the throne was not direct, but merely in preference to his mad cousin, Henry VI, whom he deposed. Three, he had a very able and powerful brother who was hungry for the kingship himself: Richard, Duke of Gloucester, who became Richard III.
The means by which Richard III came to the throne is still in dispute. Legitimate inheritance depended on disinheritance of Edward's two preteenaged sons. This could be accomplished in a number of ways: either they could be declared bastards, or they could disappear. Both occurred: Richard had Parliament pass a bill declaring his brother's second marriage to be invalid, thus turning all 11 of his children into bastards and making Richard the legitimate heir. The young princes also disappeared after a period of "protection" in the Tower of London.
All this took place when Elizabeth was a teenager. Obviously, as the eldest child of the previous King, she was a key figure in the political contests of the day, but personally seems to have been a gentle, private person who wanted no part of the struggle. She was also famous for her beauty. When Henry Tudor killed Richard during a rebellion, he secured his own somewhat tenuous claim to the throne by marrying Elizabeth.
The marriage seems to be been a success. She was 20 when they married, and the union produced seven children (or possibly eight). Henry VII was an able king who brought peace to the kingdom and time for much-needed social and economic healing after decades of civil strife. In 1501, however, the couple's eldest son and heir, Arthur, died suddenly at the age of 15. They were devastated. They had only one surviving son (a couple of others had died in infancy) and Elizabeth became pregnant again, in hopes of strengthening the succession. In early February 1503 she gave birth to a daughter, who died the same day. Elizabeth herself developed childbed fever, a postpartum infection very common in cultures where women give birth in unsanitary conditions. Nine days later, Elizabeth herself died: it was her 37th birthday.
Henry was deeply sad at her death and, despite being famous for his miserliness, gave her a splendid funeral. Elizabeth of York is the only English Queen to have been a wife, daughter, sister, niece, and mother to English kings. She's also the model for the Queen of Hearts in the traditional deck of cards.
Source: Wikipedia, Tudor History