On December 7, 1959, the UN General Assembly decided to convoke an international conference to consider the question of diplomatic intercourse and immunities. A Convention entitled "Vienna Convention on Diplomatic Relations," ranging over most aspects of the permanent diplomatic relations between States was adopted. The preamble of the treaty recognized the status of diplomatic agents and asserted that the purpose of diplomatic privileges and immunities was to ensure the efficient functioning of diplomatic missions. The packages constituting the diplomatic bag must bear visible external marks of their character and may contain only diplomatic documents or articles intended for official use. A diplomatic agent shall enjoy immunity from the criminal jurisdiction of the receiving State. With respect to acts performed by such a person in the exercise of his functions as members of the mission, immunity shall continue to subsist.