The Nobel Peace Prize has been awarded to serving heads of state or government several times since the honour was first handed out in 1901.Colombian President Juan Manuel Santos receives it Saturday for his "resolute" efforts to end five decades of war in his country, as enshrined in a historic peace accord signed with the Revolutionary Armed Forces of Colombia (FARC).Here are the precedents for Santos` honour:- 2011: Ellen Johnson Sirleaf -She was one of three women laureates along with Leymah Gbowee, also from Liberia, and Tawakkol Karman of Yemen. The committee highlighted "their non-violent struggle for the safety of women and for women`s rights to full participation in peace-building work".- 2009: Barack Obama -He was a surprise winner for his "extraordinary" diplomatic efforts on the international stage, just nine months after he took office.The Nobel committee attached "special importance to Obama`s vision and work for a world without nuclear weapons" and said he had created "a new climate in international politics".- 2000: Kim Dae Jung -He was a pro-democracy campaigner who became president of South Korea between 1998 and 2003. He won the prize in 2000, the year he helped organise a landmark reconciliation summit with North Korean leader Kim Jong-Il. Kim Dae-Jung died in 2006.- 1994: Yitzhak Rabin -Rabin, Shimon Peres and Palestinian leader Yasser Arafat jointly won the prize for their efforts to reach a peace deal between Israel and the Palestinians, resulting in the Oslo Agreement in 1993. At the time Rabin was prime minister and Peres foreign minister of Israel, while Arafat was later elected president of the Palestinian National Authority.Their goal still eludes world leaders today however.- 1993: F.W. de Klerk -As president of South Africa, de Klerk was instrumental in ending his country`s white-minority apartheid system and paving the way for majority rule. His government released from prison the man who succeeded him, African National Congress leader Nelson Mandela. The two won the prize jointly in 1993.- 1990: Mikhail Gorbachev -He was awarded the peace prize in October 1990. The reforms in part inspired by Gorbachev led to the fall of the Berlin Wall in November 1989, the reunification of Germany the following year and the effective dissolution of the Soviet Union in 1991.- 1987: Oscar Arias Sanchez -The president of Costa Rica won for his work on ending the civil wars that afflicted several central American states in the 1970s and 80s.- 1978: Anwar al-Sadat and Menachem Begin -The Egyptian president and Israeli prime minister signed the Camp David Accords in September 1978; they led to a peace deal between the two main belligerents in several Middle Eastern wars, but were followed by Sadat`s assassination three years later.US president Jimmy Carter, who presided over the deal, was to also win the prize in 2002, after he had left office.- 1971: Willy Brandt -Brandt was chancellor of West Germany -- one of the two German states that emerged after World War II -- when he won in 1971. Brandt, a social democrat, was awarded the prize for his "Ostpolitik", or policy of reconciliation with East Germany. The two states reunited to form the present-day republic of Germany in 1990.- 1921: Karl Hjalmar Branting -The Swedish prime minister, who held office twice between 1920 and 1923, won along with Norwegian historian Christian Lange. The Nobel committee hailed their support for the League of Nations.- 1919: Thomas Woodrow Wilson -Wilson was in the middle of the second of his two terms as US president when he won the prize for his work to seal the Treaty of Versailles that followed World War I. Wilson`s "Fourteen points" laid the foundations of the League of Nations, the predecessor of today`s United Nations.- 1906: Theodore Roosevelt -Teddy Roosevelt, whose name is more often associated with his role in several wars and his motto "Speak softly and carry a big stick," was awarded the Nobel Peace Prize in 1906 for helping end a war between Russia and Japan.Source: BSS