Crimean Karaites
As a result of his research he became focused on the origin of the ancestors of the Crimean Karaites who he claimed had arrived in Crimea before the common era. The Karaites, therefore, could not be seen as culpable for the crucifixion of Jesus because they had settled in Crimea at such an early date. His theories persuaded the Russian imperial court that Crimean Karaites cannot be accused in Jesus' Crucifixion and they were excluded from the restrictive measures against Jews. Many of his findings were disputed immediately after his death, and despite their important value there is still controversy over many of the documents he collected.