Sigmar Hartmut Gabriel (born 12 September 1959) is a German politician who was Minister for Foreign Affairs from 2017 to 2018 and Vice-Chancellor of Germany from 2013 to 2018. He was Leader of the Social Democratic Party of Germany (SPD) from 2009 to 2017, which made him the party's longest-serving leader since Willy Brandt. He was the Federal Minister of the Environment from 2005 to 2009 and the Federal Minister for Economic Affairs and Energy from 2013 to 2017. From 1999 to 2003 Gabriel was Minister-President of Lower Saxony. Gabriel is a member of the Seeheimer Kreis, an official internal grouping of the party with liberal economic positions.