Mendelssohn quickly rose to prominence among European banks. Starting in the 1850s, they acted as Royal bankers for the Russian Tsar, and from the 1870s dominating the Central European financial market for Russian sovereign bonds and railway bonds. Only the outbreak of World War I in 1914 and the Lenin putsch in 1917 put an end to these close contacts. The Mendelssohn family through the descendants of the founding brothers continued to run the company.