Maria of Montferrat was born in the summer of 1192 as the daughter of Queen Isabella I of Jerusalem and her first husband, Conrad of Montferrat. She never knew her father as he died before she was born. Maria had six half-siblings from her mother’s two subsequent marriages. Of those six half-siblings, four sisters survived, leaving Maria as her mother’s heiress.
The year 1205 saw the deaths of Maria’s mother, her stepfather and her infant half-brother and so a 13-year-old Maria succeeded as Queen of Jerusalem upon her mother’s death on 5 April 1205. As she was a minor her uncle, a half-brother of her mother, John of Ibelin, became regent for her. He was an effective regent. His regency expired in 1209, and in that same year, Maria was advised to marry. Philip II of France offered John of Brienne, who was funded with 40.000 livres each from Philip II and Pope Innocent III to fund his court and army. He was 22 years older than Maria. They married on 4 September 1210 and were crowned King and Queen of Jerusalem on 3 October 1210 at Tyre Cathedral. Maria became pregnant quickly and gave birth to a daughter, the future Isabella II of Jerusalem, in 1212. Tragically, Maria died not long after, probably from puerperal fever. She was still only around 20 years old.
Her daughter was proclaimed Queen at just a few days old, with her father acting as regent.