* Queen Mary I of England: She was the first Queen Regnant of England, reigning from 1553 to 1558. She was a daughter of Henry VIII and Catherine of Aragon, and her reign is often remembered for the religious persecution of Protestants, earning her the nickname "Bloody Mary." She wasn't invented, she was a historical figure.
* RMS Queen Mary: This was a British ocean liner that served as a flagship for the Cunard Line from 1936 to 1967. She was designed by a team of engineers and architects, with Bruce Ismay leading the project. She was designed and built, not invented.
So, depending on what you meant by "Queen Mary", there isn't a single inventor, but rather a team of people who built the ship, or a historical figure.