Which one of the following was not one of the causes of the revolt of 1857?

The revolt of 1857 was much more than a mere product of sepoy discontent. It was in reality a product of accumulated grievances against the Company's administration, a popular discontent and hatred against foreign rule. The most important cause was economic exploitation, the complete destruction of its traditional economic fabric, the impoverishment of the vast mass of peasants, artisans and handicraftsmen, as also a large number of traditional zamindars and chiefs. As a result of the British land and revenue policies and the system of judicial administration, a large number of peasant proprietors lost their land to traders and moneylenders and found themselves in utter debt. The complex judicial system enabled the rich to oppress the poor, and the growing poverty made them desperate. The middle and upper classes suffered by their exclusion from higher positions in the administration. Besides, Lord Dalhousie's policy of annexation of native states by applying the 'Doctrine of Lapse' was widely resented. Lastly, the conversion activities of the Christian missionaries created fear and suspicion among the general public.