Princess Elisabeth, front row second from right, is pictured here at her grandfather King Albert II's abdication – the former king is seated behind the young princess and her siblings, between wife Queen Paola and daughter-in-law Mathilde – on July 21, 2013. On the same day her father Crown Prince Philippe, on left, became the new monarch. In 1991, a decade before Elisabeth was born, a new law of succession was passed that made the monarch's first born child heir to the throne, regardless of gender. As a result, when her dad became king, Elisabeth became Duchess of Brabant, a title bestowed upon her as the heir to the throne. When Princess Elisabeth ascends the throne she will become Belgium's first Queen Regnant. Photo: Getty Images