The President of the European Council is a position in the European Union (EU) that chairs the European Council. Formerly an unofficial low-key position (also referred to as the President-in-Office), it rotated between member states every six months. Under the Treaty of Lisbon, this rotating system is replaced by a permanent post. Following ratification of the treaty by the Czech Republic on 3 November 2009, the last of the 27 member states to do so, Prime Minister Herman van Rompuy of Belgium was appointed the first permanent President of the European Council on 19 November 2009. The president-designate is expected to take office on 1 December 2009, when the Treaty comes into force and the new office comes into being.
http://en.wikipedia.org/wiki/President_of_the_European_Council