Member states holding the six-month presidency work together closely in groups of three, called 'trios'. This system was introduced by the Lisbon Treaty in 2009. The trio defines long-term objectives and prepares a common agenda on the main topics and issues the Council will deal with over an 18-month period. Based on this programme, each of the three countries prepares its own detailed six-month programme. From 1 July 2014 to 31 December 2015 the presidency trio will be made up of Italy, Latvia and Luxemburg.