The concept of trusteeship refers to the exercise of responsibility over a territory by a trustee for a limited period of time. This includes responsibility for the physical security and civil administration of the population, with the aim of promoting their eventual self-governance or independence.
The system of trusteeship was originally set up by the United Nations to help promote development for non-self-governing territories. A Trusteeship Council was established as the main organ of the UN whose responsibility was to supervise the administration of trust territories, most of which were former mandates or territories occupied before and during WWII.
Originally, the UN trusteeship system focused on post-colonial transition. However, towards the end of the 20th century, problems of collapse of governance within existing territories led to the revival of a trusteeship-like system.
Thus, contemporary trusteeships have been established either for temporary reinforcement and conservation of "failed states" or for state-building in "nascent states".