Daughter of Philip Le Bel of Burgundy and Juana La Loca of Spain.
 
At 17, she married Louis/Lajos II (Jagellon), King of Hungary, who was 15.  Four years later, the Turks over-ran half his kingdom, including the capital, Budapesht.  Louis was killed at the battle of Mohacs.  Mary fled west, taking the Hungarian treasury with her (!) Young as she was, Mary did not want to re-marry.  Instead, she asked her brother, Charles V, for a job and an income.  When their aunt, Margaret of Austria, died, Charles made Mary Regent of the Netherlands in her place.
 
Mary and Louis had no children.

Source: Sandra White