Monégasque nationality is highly protected, with only around 9,000 citizens globally. The Principality does not operate a citizenship-by-investment program; instead, foreign nationals can only acquire citizenship by birth, marriage, or a highly selective naturalization process. To apply for naturalization, an adult must have resided continuously in Monaco for at least ten years after reaching the age of 18. The petition must be written on stamped paper and addressed directly to the reigning Prince, who holds ultimate, absolute sovereign discretion over whether to grant or deny citizenship. Monaco strictly forbids dual nationality; any naturalized citizen must formally renounce all prior citizenships.