The first name of the British monarch who succeeded Queen Elizabeth II is Charles. Upon Queen Elizabeth II's passing in September 2022, her son, Charles, became king, adopting the regnal name King Charles III. His ascension marked a significant transition in British history, as Charles had spent decades as the Prince of Wales and became an important figure in charitable work and environmental advocacy. His reign begins at a time of significant societal change and challenges, as he takes on the responsibilities of the monarchy while seeking to modernize its image and address contemporary issues.