 The mission was recognized as a military expedition by the British Indian government, which issued a campaign medal, the Tibet Medal, to all those who took part.The causes of the conflict are obscure; historian Charles Allen considered the official reasons for the invasion "almost entirely bogus".It seems to have been provoked primarily by rumours circulating amongst the Calcutta-based British administration that the Chinese government (which nominally ruled Tibet) was intending to give the province to the Russians, thus providing Russia with a direct route to British India, breaking the chain of quasi-autonomous buffer-states which separated India from the Russian Empire to the north.