Sykes–Picot Agreement
When the caliphate was proclaimed, ISIL stated: "The legality of all emirates, groups, states and organisations becomes null by the expansion of the khilafah's [caliphate's] authority and the arrival of its troops to their areas." This was a rejection of the political divisions in Southwestern Asia that were established by the UK and France during World War I in the Sykes–Picot Agreement.