St Elizabeth of Hungary came from a royal family; she was the daughter of King Andrew II of Hungary. As was the custom, she was promised in marriage to the son of another noble family. Elizabeth was sent to Thuringia to be raised with her future husband. However, he died around the time of their betrothal and she married his brother, Ludwig. He was killed in a crusade several years later. The couple had three children.
Elizabeth, who even as a child strived to lead a pious and contemplative life, became a Third Order Franciscan and devoted her life to the care of the sick and the poor. She died at the very young age of 24.
Many miracles, especially of healing, were reported near her grave soon after her death. She was canonized on May 28, 1235.
St Elizabeth is usually depicted as a princess or with roses in her lap. In the case of the roses, there is a legend that as she was carrying bread to the poor on an errand of mercy, the bread she was hiding was turned into roses.
You can read a more detailed account of this saint's life here.