In 1839, long before the formation of Pakistan, British negotiator Sir Henry Mortimer Durand, the foreign secretary of the British Indian government, signed a document defining the boundary between India and Afghanistan. There is no vernacular version signed by the Afghan ruler Amir Abdur Rehman Khan, and it has been challenged as a forgery. Other accounts, however, claim that it has, in any case, expired, as it was to have been a 100-year agreement. The 1839 agreement reflected a disadvantageous military position of Britain, but the British began to enforce it circa 1893.
Most importantly, however, it does not recognize the political geography of the area, only its physical characteristics. The line cuts through traditional lands of the Pashtun people, a situation exacerbated by the formation of Pakistan. Further, it has been argued that it establishes the sovereignty of the Balochistan Province of Pakistan. There is sentiment for the formation of a Greater Pashtoonistan, just as there is one for Greater Kurdistan, neither of which appeals to the nations who would lose land from it.
While various Afghan governments have challenged it, the position of the Government of Pakistan is that it is a legitimate action of British India, inherited by the new nations under the legal doctrine of uti possidetis juris. This type of matter could be heard, as a dispute between nations, in the International Court of Justice, but never has been submitted there.