They may be young now, but one day these toddlers and young children will reign on the thrones of their countries. So who are the youngest heirs in Europe?
Hereditary Prince Jacques of Monaco:
Although born after his sister, Princess Gabriella, who is two minutes older, Hereditary Prince Jacques will one day be the Sovereign Prince of Monaco as Monaco abides by male-preference primogeniture.

Born to Prince Albert II and Princess Charlene, Jacques came into the world on 10 December 2014 in the Princess Grace Hospital.
He has three older siblings: Jazmine Grimaldi and Alexandre Grimaldi-Coste from his father’s previous relationships, and Princess Gabriella, his older twin sister.
Jacques and Gabriella will turn nine in December.
Princess Estelle of Sweden:
Princess Estelle, who just turned 11 in February, is the daughter and elder child of Crown Princess Victoria and Prince Daniel of Sweden. Her grandfather is King Carl XVI Gustaf.
In 1980, Sweden changed their laws of succession to absolute primogeniture, allowing Estelle’s mother to assume the role of Crown Princess from her younger brother, Prince Carl Philip.

Princess Estelle Silvia Ewa Mary was born on 23 February 2012 in Solna’s Karolinska University Hospital to Crown Princess Victoria and Prince Daniel.
She has one younger brother, seven-year-old Prince Oscar.
Prince George of Cambridge:
Undoubtedly the most well-known of these young future monarchs, Prince George’s birth was celebrated across the world when he was born in the Lindo Wing at St Mary’s Hospital in 2013.
As the child of the heir, George still has some time before he will ever ascend the throne as his grandfather, King Charles III, is on the throne.

Prince George Alexander Louis of Cambridge was born to the Duke and Duchess of Cambridge on 22 July 2013. He has two younger siblings: Princess Charlotte (born 2 May 2015) and Prince Louis (born 23 April 2018).
He turns ten in July.
Prince Charles of Luxembourg:
The youngest of Europe’s heirs, Prince Charles is the elder son of Hereditary Grand Duke Guillaume and Hereditary Grand Duchess Stephanie of Luxembourg. His grandfather, Grand Duke Henri, is still on the Luxembourgish throne, and Charles ranks second in the line of succession.

Prince Charles Jean Philippe Joseph Marie Guillaume was born in the midst of the pandemic on 10 May 2020. He has one brother, Prince Francois, who was born on 27 March 2023.
Charles turns three in May.