Kneissl not only invited Austrian chancellor Sebastian Kurz of the conservative Austrian People's Party (OVP) and vice-chancellor Heinz-Christian Strache of the far-right Freedom Party (FPO).

There was also a foreign guest who attracted all the attention: Russian president Vladimir Putin.

Putin sat next to the couple as they exchanged vows. Afterwards the Russian president delivered a speech in perfect German, wishing the bridal couple "much, much luck and health for their future together".

There was also a Russian Cossack choir dressed in bright red traditional clothes, Putin's personal wedding gift to the bride and groom.

The Russian leader even briefly danced with the bride, at the end of which the Austrian foreign minister went down on her knees in front of the Russian president in an apparent attempt to thank him for his presence.

These controversial pictures emerged only the day after the wedding, when they were released by Russia Today, an international television network funded by the Russian government.

Political love affair

The Austrian foreign ministry continues to maintain that the wedding was a private affair and that the Russian president was a private guest.

Yet, politics are never private love affairs. They are made up of hard facts and clear-cut, national interests.

So what were the interests on both sides here?

It is evident that for the Russian president, the Austrian foreign minister's wedding was a perfect platform to portray himself as being accepted in the West. And Russia Today was right on hand to deliver the ideal images for that.

Russia also has strong interests in cultivating a favourable relationship with Austria, which currently holds the rotating presidency of the Council of the EU.

On several occasions, the Austrian far-right FPO - which nominated Kneissl to become foreign minister and which is currently in a ruling coalition with the OVP – voiced support for lifting sanctions on Russia.

Austria was also among the very few countries not to expel any Russian diplomats following the Skripal poisoning in the UK in March.

Because of these factors, Russia considers Austria as an ally with leverage in the EU.

When it comes to the Austrian interests, there is of course the economy.

Over 700 Austrian companies are operating in Russia. According to the Austrian chamber of commerce, Austria's foreign direct investment in Russia amounted to around $7bn in 2017, despite the sanctions regime.

Austria also hosts an important gas distribution hub in the east of the country and receives about 85 percent of its gas from Russia.

Meanwhile, Vienna and Moscow have enjoyed a special relationship since the immediate post-World War II period. Russian troops left Austria in 1955 on condition that it would become a neutral country and would not join any military alliance.

Ever since, neutrality has gone hand-in-hand with good relations with Moscow. This is a policy that is largely supported across party lines.

Delicate balancing act

The strong relations between the two countries were also highlighted at the beginning of June, when Putin chose Austria as his first official working visit abroad since being re-elected Russian president in March.

During one of his previous official visits to Austria in 2001, Putin was invited to an exclusive ski resort, where he vacationed with his family and late Austrian president Thomas Klestil and his wife Margot Klestil-Loffler.

The close personal ties between Loffler-Klestil and Putin exist until this day.

It is believed that Klestil-Loffler, who is now a special representative at the Austrian foreign ministry for Russia, pulled the strings behind the scenes, and was instrumental in bringing Putin to Kneissl's wedding.

This shows there is some historical context and also precedents for Putin in Austria at official and private meetings at the same time.

The special relationship between the two countries aside, the pictures that emerged from the wedding are a symbol of a policy that seems to fail all too often.

Keeping a special relationship with Russia while being a member of the EU is a delicate balancing act. By courting Russia all too blatantly, Austria risks to lose its credibility as a bridge builder and honest broker.

Chancellor Kurz, who held a short working meeting with Putin in his limousine en route back from the wedding to Graz airport, is very determined about Austria's bridge building role.

The Austrian government had also worked hard to bring Putin's recent summit with US leader Donald Trump to Vienna, which in the end was held in Helsinki.

All of this work now risks to be undermined severely by the controversial pictures that emerged from the wedding.

It will be hard for EU members to consider Austria a neutral broker. It will also be difficult for countries in between, such as Ukraine, to respect Austria as a mediator.

This loss in credibility cannot be in Austria's interest.

As Andreas Schieder from the Austrian social democratic party asked: "how is Austria's presidency of the EU meant to live up to the government's own claims of building bridges and being an honest broker when Austria's foreign minister and chancellor are so obviously on one side?".

The Austrian government will need to find answers to this question if it wants to avoid alienating EU partners further during its presidency.

A neutral broker is in fact needed more than ever.

Mediation is not only necessary between the West and Russia but also with regard to other important upcoming issues on the EU agenda, such as migration and the integration of the Western Balkans.

Stephanie Liechtenstein is a diplomatic correspondent and freelance journalist based in Vienna, Austria