The number of delegates began to rise in the 1960s following the merging of the executive institutions of the three European Communities into a single Commission. Until recently some states had reservations accepting that EU delegations held the full status of a diplomatic mission. Article 20 of the Maastricht Treaty requires the Delegations and the Member States’ diplomatic missions to "co-operate in ensuring that the common positions and joint actions adopted by the Council are complied with and implemented".