Maria of Montferrat (French: Marie; 1192–1212), known as la Marquise, was the queen of Jerusalem who reigned from 1205 until 1212. She was the eldest daughter of Queen Isabella I and was born posthumously to Isabella's second husband, Marquis Conrad of Montferrat. She succeeded her mother as a minor under the regency of her half-uncle John of Ibelin. A search for a husband who would rule in her name began immediately, but an initial attempt to arrange a marriage with King Peter II of Aragon failed. In 1210 Maria married John of Brienne, who had been selected for her, and was crowned alongside him. John of Brienne took over the government from John of Ibelin and Maria consented to his acts as king. She died shortly after giving birth to her only child, Isabella II, who succeeded her as queen under King John's guardianship.