Newly available data on Russian commerce, industry, finance, incorporations, labour, and investment allow a fresh approach to two historical puzzles: the dating of cyclical peaks and troughs in Russia during the six decades before the First World War and the evaluation of theories advanced to explain the causes of these cycles. A diffusion index and a composite index establish the dates and amplitudes of seven complete cycles from 1855 to 1909 and part of an eighth, in 1910–13, interrupted by the First World War. The influence of wars and the Revolution of 1905 on the Russian cycle is clear. A comparison of diffusion indices for Russia and Germany reveals that Russian cycles occasionally diverged from the European pattern in the absence of war and revolution, notably during the industrial boom of the 1890s. The new findings give qualified support to the contention of several Soviet economists in the 1920s that this divergence resulted, at least in part, from the monetary stimulus of exports, primarily of grain.