Liechtenstein marked its National Day on Saturday, and as the landmark moment was celebrated, the royal family made a major announcement.

The small European nation remains the only monarchy on the continent to operate under agnatic primogeniture rules, meaning that women are not allowed to inherit the throne, with second-born sons coming before first-born daughters.

However, in a statement, the monarchy confirmed it would now be moving to absolute primogeniture, the favoured model of European monarchies, although Monaco still operates with a male-favoured primogeniture ruling.

"Dear citizens of Liechtenstein, the ability to combine continuity with renewal is a principle we also uphold within the Princely House," the statement read. "Throughout our centuries-long history, we have benefited greatly from making decisions with a long-term perspective and careful deliberation.

"I am pleased to inform you today of a decision of great importance to our House—one that has been discussed within the family, in part, for decades. It entails an amendment to the House Law; concrete work on this began late last year, and on Wednesday, it secured the necessary two-thirds majority among family members entitled to vote.

"This amendment grants all female descendants of the Princely House the same rights of participation in matters concerning the House Law as their male counterparts. Furthermore, the order of succession is shifting from male primogeniture to absolute primogeniture. This means that, in the future, the firstborn child—regardless of gender— will become the heir to the throne and, subsequently, the Princess or Prince of Liechtenstein."

Liechtenstein's current monarch is Prince Hans-Adam II, and he has been the head of their royal family since 1989. The rule change won't affect his heir, Hereditary Prince Alois, who was his first-born. Hans-Adam's only daughter, Princess Tatjana, was his fourth child.

Hereditary Prince Alois' children also won't be affected by the move, as his first-born child was his son, Prince Joseph Wenzel, who is currently second in line to the throne. Prince Joseph Wenzel is currently unmarried and doesn't have any children, but if the 31-year-old's first issue is a daughter, then she would become the first Princess of Liechtenstein in the country's history.

The Liechtenstein monarchy hail from the house of Liechtenstein, currently helmed by Prince Hans-Adam. While other monarchies can have their roles and responsibilities curtailed by parliament, the membership, rights and duties of the family are decided solely by votes from the family's dynasts.

During his reign, Hans-Adam has seen his powers increase dramatically, mostly through a 2003 referendum, which gave Hans-Adam the power to dismiss the government and appoint judges – at the time, it was reported that this in effect made Liechtenstein an absolute monarchy.

In the lead-up to the vote, Hans-Adam declared that he would abdicate and exile himself from the country if the powers weren't approved.

Despite the new powers, Hans-Adam relinquished most of these powers to his son, Hereditary Prince Alois, a year later, on 15 August 2004. Although he no longer runs day-to-day government decisions, Hans-Adam remains as the country's head of state.