When theatrical producer Ed Opalsen was about to mount a production of "Pearls Before Swine", he bought a famous strand of pearls to use in the show for publicity.
The pearls were from the 1908 production of "Salome", a silent movie starring Russian actress and dancer Natalya Dolzhenka. The pearls were given to her as a gift from the Tsar of Russia.
In 1908 here in the real world, there were three film productions based on Oscar Wilde's "Salome":
"Salome, or The Dance Of The Seven Veils"
"L' Inconsciente Salome"
None of them, so far as I can tell, starred any Russian actress named Natalya Dolzhenko. (Movies from one hundred years ago, the IMDb.com was lucky there was still enough info around that these three movies existed!)
Of course, we're dealing with Toobworld, so it doesn't really matter. This is just one of the many trivial details in which the TV Universe differs from our Trueniverse. Over there, four versions of the play were filmed, and that strand of pearls became the center of a "Jewel Robbery At The Grand Metropolitan", which only 'Poirot' could solve.
By the way, the closest I can find to the name of this actress in the real world is Natalia Dolzhenko, who pops up on several internet scammer lists as a woman from Ukraine who deceives overly trustful men.
I wonder if she got her inspiration for that name from Agatha Christie?