The Convention on International Civil Aviation (also known as Chicago Convention), was signed on 7 December 1944 by 52 States. Pending ratification of the Convention by 26 States, the Provisional International Civil Aviation Organization (PICAO) was established. It functioned from 6 June 1945 until 4 April 1947. By 5 March 1947 the 26th ratification was received. ICAO came into being on 4 April 1947. In October of the same year, ICAO became a specialized agency of the United Nations linked to Economic and Social Council (ECOSOC). 
The Convention on International Civil Aviation set forth the purpose of ICAO:
- “WHEREAS the future development of international civil aviation can greatly help to create and preserve friendship and understanding among the nations and peoples of the world, yet its abuse can become a threat to the general security; and
- “WHEREAS it is desirable to avoid friction and to promote that cooperation between nations and peoples upon which the peace of the world depends;
- “THEREFORE, the undersigned governments having agreed on certain principles and arrangements in order that international civil aviation may be developed in a safe and orderly manner and that international air transport services may be established on the basis of equality of opportunity and operated soundly and economically;
- “Have accordingly concluded this Convention to that end.”
ICAO was originally created to promote the safe and efficient development of civil aviation. One enduring aspect of the Organization's work over the last six decades has been to help States improve civil aviation in their country through projects implemented under ICAO's Technical Cooperation Programme. Since its creation in 1952, the Technical Cooperation Bureau (TCB) has been responsible for the execution of ICAO’s Technical Cooperation Programme advising and assisting States, donors, the private sector and other funding sources in all matters relating to the development of safe and secure civil aviation. To this day the Technical Cooperation Programme remains a permanent priority activity of ICAO which complements the technical role of the Regular Programme by supporting Member States in the implementation of ICAO regulations, policies and procedures. The Technical Cooperation Programme is conducted under the broad policy guidance of the ICAO Assembly and of the Council. Subject to general guidance by the Secretary General, the Technical Cooperation Programme is executed under delegated authority by the Technical Cooperation Bureau (TCB), under its Director. 