The Queen of Halloweentown is the un-named wife of Marvin and the mother of Splendora Agatha Cromwell. Like her husband she is never seen in the films and unlike her husband she is never mentioned. The Queen is referred to as the Queen of Halloweentown because her daughter was the next Queen in Halloweentown, so naturally Aggie's mother would be the former Queen. Her husband was not a warlock as Dylan was said to be the first male warlock in the Cromwell family. This would mean that the family name Cromwell is from the Queen's lineage as throughout the films multiple characters say that the Cromwell family are very powerful witches. If this is the case it could mean that all the witches in the Cromwell family (with the exception of Gwen) kept their maiden names. Another possibility could be that the Queen took the name Cromwell from her husband and started the Cromwell line of witches.