possession of one of the highest ridges in the regions. The high altitude and freezing conditions also caused logistical and welfare difficulties; in past similar conflicts (such as the Italian Campaign of World War I) harsh conditions have caused more casualties than have enemy actions. The Sino-Indian War was no different, with many troops on both sides succumbing to the freezing cold temperatures. Background The main cause of the war was a dispute over the sovereignty of the widely separated Aksai Chin and Arunachal Pradesh border regions. Aksai Chin, claimed by India to belong to Ladakh and by China to be part of Xinjiang, contains an important road link that connects the Chinese regions of Tibet and Xinjiang. China's construction of this road was one of the triggers of the conflict. Aksai Chin The western portion of the Sino-Indian boundary originated in 1834, with the conquest of Ladakh by the armies of Raja Gulab Singh (Dogra) under the suzerainty of the Sikh Empire. Following an unsuccessful campaign into Tibet, Gulab Singh and the Tibetans signed a treaty in 1842 agreeing to stick to the "old, established frontiers", which were left unspecified. The British defeat of the Sikhs in 1846 resulted in the transfer of the Jammu and Kashmir region including Ladakh to the British, who then installed Gulab Singh as the Maharaja under their suzerainty. British commissioners contacted Chinese officials to negotiate the border, who did not show any interest. The British boundary commissioners fixed the southern end of the boundary at Pangong Lake, but regarded the area north of it till the Karakoram Pass as terra incognita. The Maharaja of Kashmir and his officials were keenly aware of the trade routes from Ladakh. Starting from Leh, there were two main routes into Central Asia: one passed through the Karakoram Pass to Shahidulla at the foot of the Kunlun Mountains and went on to Yarkand through the Kilian and Sanju passes; the other went east via the Chang Chenmo Valley, passed the Lingzi Tang Plains in the Aksai Chin region, and followed the course of the Karakash River to join the first route at Shahidulla. The Maharaja regarded Shahidulla as his northern outpost, in effect treating the Kunlun mountains as the boundary of his domains. His British suzerains were sceptical of such an extended boundary because Shahidulla was away from the Karakoram Pass and the intervening area was uninhabited. Nevertheless,