Treaty Between the British, Sikhs and Afghans
As the rumours of Russian infiltration into Persia and Afghanistan spread in the late thirties of the nineteenth century, the Governor-General, Lord Auckland, despatched Captain Alexander Burnes to Kabul to make an alliance with Amir Dost Muhammad. The Afghan ruler made Peshawar the price of his co-operation which the British could not afford without going to war with the Sikhs.
Auckland had to choose between Dost Muhammad and Ranjit Singh. He chose Ranjit. Singh and decided to seek his help in ousting Dost Muhammad and putting Shah Shuja' on the throne of Afghanistan. In April 1838, Burnes' mission was withdrawn from Kabul. In May 1838, Sir William Macnaghten was deputed to Lahore to engage the Maharaja in a treaty which aimed at the revival of the defunct Sikh-Afghan agreement of 1833. After prolonged negotiations, the treaty was signed by Ranjit Singh on 26 June 1838 which is known as the Tripartite Treaty. The Treaty confirmed control of the Sikh kingdom, in perpetuity, over the former Afghan possessions of Kashmir, Attock, Hazara, Peshawar and its dependencies up to the Khaibar, Bannu, Tonk, Kalabagh and other dependent Waziri districts, the Derajat and the rich and fertile province of Multan. For relinquishing its claims to Shikarpur, the Lahore Government, under British mediation, was to receive a sum of 1,500,000 rupees out of the levy on the Amirs of Sindh. Shah Shuja' renounced all his claims in regard to Sindh and agreed to abide by the settlement made by the British and the Sikh ruler in Sindh. Shah Shuja' surrendered to joint Anglo-Sikh authority control of the foreign relations of Afghanistan. The Lahore Government bound itself, for an annual payment of 200,000 rupees by the Shah, to maintain a Muhammadan auxiliary force of not fewer than 5,000 men for the Shah's aid. Finally, Hirat was to be independent, and, at Kabul, Shah Shuja' was required to have a British envoy. It has been said that the real purpose of the British in working out the Tripartite treaty was to thwart Sikh designs on Sindh.
:Encyclopaedia of Sikhism - Harbans Singh