Queen Isabella II's husband Francis had the title of His Majesty The King of Spain from October 10, 1846 to June 25, 1870. He had the title of His Majesty King Francis of Spain from June 25, 1870 to April 17, 1902.
Was Francis a reigning King?
No, he was king consort, something that other European royal husbands have vindicated to date. In that sense, Spanish royals proved to be equalitarian. The fact of his being a Spanish Infante may have been taken into account too.