European defence integration gained momentum soon after the end of the Cold War, partly as a result of the EC's failure to prevent the Yugoslav Wars. In 1992, the WEU was given new tasks, and the following year the Treaty of Maastricht founded the EU and replaced the EPC with the Common Foreign and Security Policy (CFSP) pillar. In 1996 NATO agreed to let the WEU develop a so-called European Security and Defence Identity (ESDI). The 1998 St. Malo declaration signalled that the traditionally hesitant United Kingdom was prepared to provide the EU with autonomous defence structures. This facilitated the transformation of the ESDI into the European Security and Defence Policy (ESDP) in 1999, when it was transferred to the EU. In 2003 the EU deployed its first CSDP missions, and adopted the European Security Strategy identifying common threats and objectives. In 2009, the Treaty of Lisbon introduced the present name, CSDP, while establishing the EEAS, the mutual defence clause and enabling a subset of member states to pursue defence integration within PESCO. In 2011 the WEU, whose tasks had been transferred to the EU, was dissolved. In 2016 a new security strategy was introduced, which along with the Russian annexation of Crimea, the British withdrawal from the EU and the election of Trump as US President have given the CSDP a new impetus.