The princess, who went to school in Wales and started three years of military training in Spain in August, vowed to uphold the law, respect the rights of citizens and regions and be faithful to the king.
Princess Leonor is the eldest daughter of King Felipe VI and Queen Letizia of Spain. She was born on October 31, 2005, in Madrid, Spain, and her full name is Leonor de Todos los Santos de Borbón y Ortiz.
Princess Leonor also held the title of Princess of Asturias, which is the traditional title for the heir to the Spanish throne. She has a younger sister, Infanta Sofia, who was born on April 29, 2007.
Princess Leonor is in line to become the future queen of Spain, following her father, King Felipe VI.
Princess Leonor's education and public duties are being carefully prepared to equip her for this role, and she is expected to play an increasingly prominent role in Spanish and international affairs as she grows older.
Like her parents, Princess Leonor is multilingual and speaks several languages. In addition to Spanish, she is known to be fluent in English, which is an important skill for a future head of state with international responsibilities.