a state visit to France to attend the Exposition Universelle (1855). During their visit, their dissimilarities were again the cause of comment. Marie Henriette was described as strong, vivid and energetic and Leopold as serious, dry and physically weak: Marie Henriette as extrovert, Leopold as introvert. Pauline de Metternich wrote that theirs was a marriage "between a stable-boy and a nun, and by nun I mean the Duke of Brabant". In 1856, her cousin Archduke Maximilian visited the Belgian court to meet his future wife, Marie Henriette's sister-in-law Charlotte. He estimated that Marie Henriette must have had help from her lively intelligence to overcome many sensitive situations and that she brought some life to the Belgian royal family. In 1858, Marie Henriette gave birth to her first child. The fact that the child was a girl was a cause of disappointment. The future heir to the throne was finally born in 1859. In 1860 and in 1864, Leopold made two more long health trips, this time without Marie Henriette, the last trip to Egypt, Ceylon, India and China. Both trips were made when Marie Henriette was pregnant, and she expressed her disappointment in being left at home with the children while he was making long journeys to faraway lands. Queen On 10 December 1865, King Leopold I died and was succeeded by his son Leopold II, making Marie Henriette queen. When the king was enthroned, there were questions as to whether Marie Henriette should participate, but the king refused and the queen was instead reduced to being a spectator at the ceremony. Marie Henriette and Leopold still lived together during the first seven years as king and queen, but their relationship was distant, and Leopold was described as a polite but authoritarian husband. Marie Henriette was interested in opera and theatre and often visited the Royal Theatre of La Monnaie, where the royal box was extended with a private room where the queen could socialize with a circle of private friends she gathered over the years. In 1867, her sister-in-law empress Charlotte of Mexico was imprisoned for mental instability by her in-laws, the Habsburgs. Marie Henriette was given the assignment by Leopold to negotiate Charlotte's release to Belgium. She went to Vienna with her advisor baron Adrien Goffinet, and succeeded in her task after two weeks of negotiations. Charlotte initially stayed with the royal couple at Laeken, were Marie Henriette