Most of what I know, was always known. All I have discovered is the Aizenman connection. My father’s aunt and uncle were grandchildren of the immigrant, Benjamin Matveevich. They had first cousins in Russia that they stayed in touch with throughout their lives. Benjamin and his wife Henrietta Khan were both born in Riga. He was ethnically German, although the family was originally Belgian. His dissertation director was Alexander von Humboldt and he corresponded with Marx. Riga was Russian, and Benjamin and Henrietta moved to St. Petersburg. They lived in Russia without being Russians themselves, but their children felt Russian.
Benjamin was to be deported to Siberia in 1862 due to the correspondence with Marx, but Henrietta had a friend at court who was able to intervene. Banned from Russia, they went to Zurich and then the US, arriving in 1865. Some of their children, including William Veniaminovich and Alexander Veniaminovich, returned to Russia in 1877. My great-grandfather, Emil Veniaminovich, did not. Alexander’s children, born in Russia from 1879 forward, were my grandfather’s first cousins. My grandfather and his brother and sister were close to them, and I corresponded with one of Alexander’s daughters, Lidia, until she died in 1987. Alexander became a prominent person in Russia and is a historical figure of some interest.
My friend Nicky recently did an Internet search in Russian for Alexander. Alexander is on Wikipedia and people blog about him, as he is a piece of history (he was a friend of Tolstoi, Pasternak; children are later friends of Akhmatova; you can see that they are cultured as well as technologically advanced). There are even people who have designed walking tours of Moscow around him. You can see the old factory, the office, the house, and some important structures (railway stations, the Pushkin Museum, towers) that he and his partner Vladimir Shukhov (a truly major figure, Lenin Prize 1929) built.
It is by following the links in these sites on Alexander that I discovered the art of his daughter Olga and of her son Alexei. Her husband was a professor at Moscow State until the Revolution. Her daughter Tatiana was a folk art critic, and her granddaughter Anna is a sculptor working now. Here we have a long article with news of these cousins we did not know. Those living in cities occupied by the Germans wore yellow stars and were shot. Those living now are friends with me on Facebook.