Princess Leonor, the eldest daughter of King Felipe VI and Queen Letizia, holds a unique position in the Spanish royal family. Born in Madrid on October 31, 2005, Leonor became the heir to the Spanish throne when her father became king on June 19, 2014, following the abdication of King Juan Carlos I. Leonor is officially known as the Princess of Asturias. Asturias is a Spanish region located in the northwest of the country, which was named a principality in 1388 by King John I of Castile to bestow the title of Prince of Asturias on his eldest son, Henry. When Leonor succeeds her father, she will become Spain’s first reigning queen since Isabella II, who ruled from 1833 to 1868.
Her position is especially notable because Spain still follows male-preference primogeniture under its Constitution. This means that, if Leonor had a younger brother, he would have taken priority over Leonor to the throne. Changing this system would require an amendment to the Spanish Constitution, which has been in force since 1978. Spain is now one of only two European monarchies, alongside Monaco, where this system remains in place. 
Meanwhile, Sweden, the Netherlands, Norway, Belgium, Denmark, Luxembourg, and the United Kingdom have replaced male-preference primogeniture and now utilize absolute primogeniture. This means that the king or queen’s first child will also be first in line to the throne, regardless of gender. Leonor is also preparing for the responsibilities that could come with ascending to the throne. As a soon-to-be queen, she will become head of Spain’s Armed Forces. In that line, she has completed military training at the General Military Academy, the Naval Military Academy, and the General Air and Space Academy. Therefore, her future coronation represents both a major historical moment for Spain and a significant responsibility for the young royal.
