The waltz, originally a German country dance, appeared in revolutionary France in 1793, and spread from Napoleon's Court to St. Petersburg and Vienna. Madame de Lieven brought it to England in 1812, but did not venture to dance it at Almack's until Tsar Alexander, on his visit to London in 1816, danced it there with her. A dance in which the man seized his partner around the waist and clasped her to him, in public, had not been known in polite society since the sixteenth century, and it naturally created a sensation; and in the atmosphere of Almack's in Regency days, it could hardly have the innocent significance which it had, as an already established custom, in staid Victorian times. Even after the Tsar had set an example, most members hesitated to dance the waltz; but Captain Gronow states that in course of time Palmerston might be seen 'describing an infinite number of circles with Madame de Lieven', and the Austrian chargé d'affaires, Baron Neumann, waltzed regularly with the Princess Esterhazy.-- Jasper Ridley, Lord Palmerston, at 43.
The Princess Lieven (a German married to a Russian noble) was at different times the mistress of Guizot and of Metternich, and had more to occupy her mind than waltzes:
Princess Lieven “succeeded in inspiring a confidence” with prominent men “until now unknown in the annals of England”, wrote Russian foreign minister Count Nesselrode. Her friendships with George IV, Prince Metternich, the Duke of Wellington, George Canning, Count Nesselrode, Lord Grey, and François Guizot gave Dorothea Lieven the opportunity to exercise authority in the diplomatic councils of Great Britain, France, and Russia. She was a political force, a position reached by no other contemporary female.That was ungracious of Palmerston to his erstwhile dancing partner and, it may be, mistress.
The Princess participated, either directly or indirectly, in every major diplomatic event between 1812-1857. She knew “everyone in the Courts and cabinets for thirty or forty years”; she “knew all the secret annals of diplomacy”, wrote a French diplomat. Palmerston seems to have resented her interference, writing " a busy woman must do harm because she can do no good."
There seem to have been a couple of English biographies of her, none in print. This 1903 review by Sydney Smith of one volume of her many letters (they are important sources for diplomatic history) goes into her biography in some detail, including her introduction of the waltz to England -- in 1816, says Smith.
... Nicholas I's deficiencies as a human being have been well recorded by Edward Crankshaw and others, but Smith's review provides a new example. The Tsar did not approve of the princess's leaving Russia to settle in Paris, after two of her sons had died in St. Petersburg:
Incredible as it may seem, he did not permit her husband to announce to her the death of a third son, which she only learned through a letter addressed to him being returned to her through the post with the word 'Dead' written on the envelope.... And she was a Lutheran! Philip Mansel, Paris Between Empires: Monarchy and Revolution 1815-1848, at 334. Her [husband's] family was Baltic German, tho she seems to have identified strongly with Russia. [Correcting basic stupidity on my part.]