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Isabel von Habsburg-Lothringen, Archduchess of Austria, tied the knot with a Spanish aristocratic in an elegant ceremony attended by Belgian royalty on Saturday.

In a joyous event which brought two nation's royal families together, the great-granddaughter of Emperor Karl and Empress Zita of Austria wed Carols de Palacio Gaytan de Ayala at Vienna's Jesuit Church.

Among the star-studded guests who gathered to witness the couple's nuptials on July 25 were King Philippe and Queen Mathilde of Belgium, alongside their two eldest children, Princess Elisabeth and Prince Gabriel.

Isabel, 26, who is the daughter of Archduke Simeon of Austria and his wife, Princess Maria of Bourbon-Two Sicilies, holds historic family ties to the Belgian Royal Family.

Indeed, King Philippe's sister, Princess Astrid, is the wife of Prince Lorenz, Archduke of Austria-Este, who are a cadet branch of the Habsburg Lorraine.

Meanwhile, Carlos is the son of Carlos Maria de Palacio y de Oriol and Teresa Gaytan de Ayala y Dominguez and descends from Spanish nobility.

Stepping out for her wedding day in a striking A-line silk dress with a floral lace bodice, Isabel donned the Bourbon-Two Sicilies diamond button tiara, which she borrowed from her uncle, the Duke of Calabria.

The elegant tiara was also worn by Isabel's mother on her wedding day and was first gifted to Princess Alicia of Bourbon-Parma for her wedding to Infante Alfonso, Duke of Calabria, in 1936.

Alongside the historic tiara, the bride also accessorised with her mother's pearl earrings, which she wore on her own wedding day to the Archduke in 1996.

Isabel von Habsburg-Lothringen, Archduchess of Austria, tied the knot with Carlos de Palacio Gaytan de Ayala in a glamorous ceremony attended by Belgian royalty on Saturday

Isabel, 26, who is the daughter of Archudke Simeon of Austria and his wife, Princess Maria of Bourbon-Two Sicilies, holds historic family ties to the Belgian Royal Family which spans decades

Among the star-studded guests who gathered to witness the couple's nuptials were King Philippe and Queen Mathilde of Belgium , alongside their two eldest children, Princess Elisabeth and Prince Gabriel

Despite their family heritage and their regal wedding guest list, both Isabel and Carlos are based in London and work in finance.

Isabel, who has a Philosophy, Politics and Economics degree from the University of Navarra, works as an analyst for Fremman Capital, while Carlos holds a Senior Associate position in Mubadala Capital's Private Equity team.

Arriving in style at the royal wedding, Princess Elisabeth, 24, opted for a glamorous emerald green pleated Maje dress, alongside Maison Fabienne Delvigne clutch bag and coordinated fascinator to tie the look together.

Taking fashion inspiration from the Princess of Wales, Elisabeth, who is heir to the Belgian throne, wore a pair of Givanvito Rossi's Gianvito 105 Suede Pumps in Praline.

Her mother, Queen Mathilde, 53, looked effortlessly elegant in a red lace dress, which she paired with matching heels and a headpiece.

Notably absent from the wedding day were the family's two youngest members, Prince Emmanuel, 20, and Princess Eleanore, 18.

Other high-profile guests who were in attendance for the all-important nuptials were Countess Anna Schaffgotsch and Infante Dinis de Braganca, alongside Pierre D'Arenberg and Princess Lydia Athenais D'Arenberg

Showcasing the close bond between royals from different nations, Elisabeth, 24, gave insight into arguably the world's most exclusive group chat, with Crown Princesses Catharina-Amalia of the Netherlands, 22, and Ingrid Alexander of Norway, 22, in a recent interview.

Stepping out for her wedding day in a striking A-line silk dress with a floral lace bodice, Isabel donned the Bourbon-Two Sicilies diamond button tiara, which she borrowed from her uncle, the Duke of Calabria

Pictured: Isabel's veil as she arrived at the church for her wedding day. Alongside the historic tiara, the bride also accessorised with her mother's pearl earrings, which she wore on her own wedding day to the Archduke in 1996

Queen Mathilde, 53, looked effortlessly elegant in a red lace dress, which she paired with matching heels and a headpiece

Isabel, who has a Philosophy, Politics and Economics degree from the University of Navarra, works as an analyst for Fremman Capital, while Carlos holds a Senior Associate position in Mubadala Capital's Private Equity team

The royal, who recently graduated her two-year master's degree at Harvard University, told HNL via People in her first major interview: 'We've known each other for a long time and see each other occasionally at events.

'In my generation, there are several women. You see a similar shift in other monarchies,' she said, before adding, 'we are all in the same situation. It's a hurdle we will face together.'

In June last year, Catharina-Amalia also told journalist Wim Dehandschutter via Australia Women's Weekly: 'We stay in contact with each other because we are all living a very specific life and we don't need much explanation to understand each other.'

She added: 'It's a good thing that I can chat with Elisabeth and Ingrid Alexandra about very simple things in our life which are difficult, different for us, friendships, privacy, social media. We discuss how we handle it.'

It's thought Spain's 20-year-old Leonor, Princess of Asturias, who graduated from UWC Atlantic in South Wales and is now training in the Spanish military, may also be included in the closely-guarded WhatsApp group.

However, Wim admitted he couldn't be sure because her mother Queen Letizia of Spain is 'very strict' with her two daughters, meaning the heir to the Spanish throne is apparently less connected than the other three princesses.

Further explaining the royal support network built by the future queens, the journalist revealed how Catharina-Amalia mentioned privacy as a topic of discussion for the princesses.

Wim questioned: 'How do you handle privacy when you're a public figure? How do you react when people want to become friends? Do they want to become friends because you are the future queen or do they really like you?'

The Princess of Orange is the eldest child of Queen Maxima and King Willem-Alexander of The Netherlands, and has recently begun to take on solo engagements and more responsibility within the royal household.

Catharina-Amalia, who is first in line to the throne ahead of her siblings Princess Alexia, 20, and Princess Ariane, 19, is said to speak fluent Spanish thanks to her mother, who is Argentine by birth.

She is currently studying for a degree in Politics, Psychology, Law and Economics at Amsterdam University.