Russia on Friday held its first royal wedding since the 1917 Bolshevik revolution toppled the Romanov monarchy, with aristocrats travelling from across Europe for the lavish ceremony.

Grand Duke George Mikhailovich Romanov, 40, and his Italian fiance Rebecca Virginia Bettarini, 39, were wed at Saint Isaac's cathedral in the former imperial capital Saint Petersburg.

Hundreds of foreign guests travelled to Russia's second city for the Orthodox Christian ceremony, including royals from 20 countries such as the last king of Bulgaria, Simeon II, the last king of Egypt and the Sudan, Fuad II, and Princess Lea of Belgium.

The guest list of around 1,500 people included other prominent names like Konstantin Malofeyev, a monarchist and billionaire close to the Kremlin, and Russian foreign ministry spokeswoman Maria Zakharova.

Bettarini converted to the Orthodox faith last year.

Young bridesmaids dressed in orange carried the bride's train that featured the coat of arms of the Russian Empire, embroidered in gold.

Bettarini also wore a diamond-encrusted tiara made by high-end jewellers Chaumet.

Surrounded by priests in golden robes, Romanov and Bettarini beamed as Metropolitan Varsofony of Saint-Petersburg and Ladoga performed the blessing.

Metropolitan Varsofony praised the couple for their desire to serve Russia.

"We are happy that you love Russia, and take part in charity projects," he said.

The ceremony included the exchange of wedding rings made by Faberge.

The House of Faberge said it was the first time it had created wedding rings for members of the Romanov family "since before the Russian revolution".

Some women sported designer hats and furs, and men wearing Cossack uniforms decorated with medals could also be seen.

Natalya Grigorovich, a descendant of Ivan Grigorovich, Tsarist Russia's last naval minister, described the ceremony as "touching".

"My heart rejoices," she added.

Passing by Saint Isaac's cathedral, Saint Petersburg resident Galina Bobrova said she wished the couple "happiness".

"For us the monarchy is something from a past life, of course, but it's interesting," the 50-year-old told AFP.

After the ceremony the sword-bearing honour guard saluted the newlyweds as they kissed outside the cathedral.

More than 500 guests were invited to attend the wedding dinner at the city's Museum of Ethnography later Friday.

The last wedding in Russia of an heir to the Romanovs was that of Nicholas II and Alexandra, 127 years ago.

Ahead of the ceremony, Romanov said the couple chose to tie the knot in Saint Petersburg because it was the first place in the country where the family returned in the early 1990s.

"It is very, very close to our family," he told Saint Petersburg-based news website Fontanka ahead of the wedding.

Saint Petersburg is "the history of Russia," he added, "the history of the House of Romanov".

Born in Madrid, Romanov is the son of Grand Duchess Maria Vladimirovna Romanova, the self-proclaimed heir to Russia's imperial throne.

She is the granddaughter of Grand Duke Kirill, a cousin of Nicholas II, the last Russian tsar who was executed along with his wife Alexandra and five children by the Bolsheviks in 1918.

Buried after their execution in a place long kept secret by the Soviet authorities, their bodies and those of their children were transferred in 1998 to the Peter and Paul Cathedral in Saint Petersburg.

The family was canonised by the Orthodox Church in 2000 as martyrs.

After the wedding the newlyweds laid flowers at the Peter and Paul Cathedral.

Romanov, who spent much of his life in France, graduated from Oxford and worked in the European Parliament. He also held jobs at Russian mining giant Norilsk Nickel.

The couple moved to Russia three years ago, settling first in the Moscow suburbs before relocating to the city centre next to the Kremlin.

Romanov now works on several charity projects.

He said he believes European and Russian royals could help Moscow and the West mend fraying ties.

Vladimir Putin's spokesman told reporters that the Kremlin always wished all newlyweds happinesses but the president did not plan to congratulate the couple.

"This marriage does not belong on our agenda in any way," said Dmitry Peskov.