The Spanish monarchy has distinct differences. While Leonor holds the title of Princess, her sister Sofia is limited to being just an Infanta, even though both are daughters of King Felipe VI and Queen Letizia.
The reason behind this has nothing to do with favoritism or who is more loved at home. It has to do with rules.
There is a historical and legal explanation for the difference in their titles.
Why is Infanta Sofia not a Princess?
Leonor, as the eldest, is the Princess of Asturias. Why? Because she is the one who will inherit the throne and become the future queen.
According to Royal Decree 1368/1987, it is explicitly stated: the first son or daughter of the reigning king or queen automatically becomes Prince or Princess of Asturias, along with inheriting other ancient titles.
Thus, Leonor is being prepared to lead the royal household and to become the next queen of Spain.
In Sofia de Borbón’s case, as the younger daughter, she is not in the direct line of succession. That is, she will not reign. Therefore, the same decree stipulates that she is given the title Infanta of Spain and is addressed as Her Royal Highness.
However, this does not mean that she remains uninvolved in royal life. Infanta Sofia also participates in official events and accompanies her parents and her sister Leonor to important occasions. But her role is different, as she is not destined to wear the crown.
The key difference between a Princess and an Infanta in Spain lies in the line of succession.
The Princess is the heir, the person who will become the next queen or king. Currently, that honor belongs to Leonor, the eldest daughter of King Felipe.
An Infanta, on the other hand, is the daughter of the king or queen who is not first in line to inherit the throne. That is why Sofia is an Infanta—although she is the daughter of Felipe and Letizia, she will not become the next queen. It is as simple as that.