One role American presidents and their secretaries of state and envoys often have played with great success is helping bring peace to fractured parts of the world.

Three sitting presidents, five current or former secretaries of state, a former president and a former vice president are among the 21 Americans who have won Nobel Peace Prizes for their efforts.

Here is a look at celebrated deals they brokered:

Sudan’s Comprehensive Peace Agreement (2005)

Colin Powell and two others sitting in front of three people standing (© Thomas Mukoya/Reuters)
Secretary of State Colin Powell (left) joins leaders of Sudan’s government and rebels in signing the 2005 accord. (© Thomas Mukoya/Reuters)

The pact between the Sudanese government and the Sudan People’s Liberation Movement ended Africa’s longest civil war and laid the groundwork for the 2011 referendum that gave South Sudan its independence. The United States played an important role in the negotiations, with Secretary of State Colin Powell among the principal signatories.

Good Friday Agreement (1998)

Group of people standing around seated George Mitchell, clapping (© Elise Amendola/AP Images)
Former U.S. Senator George Mitchell receives a round of applause at a 1998 ceremony in Boston honoring him and Northern Ireland leaders for the Good Friday Agreement that ended three decades of sectarian strife in Ulster. (© Elise Amendola/AP Images)

Longstanding enmity between Northern Ireland’s Protestant majority and Catholic minority erupted into strife in 1968. The conflict, which lasted three decades, was regarded as one of the world’s most intractable ethnic disputes. But the Good Friday Agreement signed in 1998 brought durable peace to the divided province of Ulster. U.S. Special Envoy and former Senate Majority Leader George Mitchell crafted the ground rules in 1996 that brought the disputants to the table and shuttled between Washington and Belfast to close the deal.

The Dayton Accords (1995)

People sitting and standing clapping (© Jerome Delay/AP Images)
President Bill Clinton (standing, second from left) and European leaders applaud as Balkan leaders Presidents Slobodan Milosevic of Serbia, Franjo Tudjman of Croatia and Alija Izetbegovic of Bosnia and Herzegovina sign the 1995 accords that ended the Bosnian War. (© Jerome Delay/AP Images)

The Dayton Accords signed by Serbia, Croatia, and Bosnia and Herzegovina in 1995 ended the war in Bosnia that claimed over 200,000 lives. American diplomat Richard Holbrooke was the chief negotiator for the agreement hammered out at a peace conference in Dayton, Ohio, led by Secretary of State Warren Christopher and leaders of Europe and Russia.

Camp David Accords (1978)

Three seated men talking (White House/AP Images)
Egyptian President Anwar Sadat, President Jimmy Carter and Israeli Prime Minister Menachem Begin meeting at Camp David, Maryland, on September 6, 1978. Sadat and Begin did not meet again during the 13-day summit; Carter went back and forth between them with new positions. (White House/AP Images)

The historic peace treaty that Egyptian president Anwar Sadat and Israeli prime minister Menachem Begin signed at the White House on March 26, 1979, ended the 30-year state of war between the Middle East neighbors. The treaty brought to fruition the Camp David Accords agreed upon in September 1978. President Jimmy Carter brought Sadat and Begin to the presidential retreat in Maryland’s Catoctin Mountains and served as the go-between for the 13-day summit. Sadat and Begin were awarded the 1998 Nobel Peace Prize.

A Nobel Peace Prize for Arbitrating Conflicts (1912)

Elihu Root with others in line (© Buyenlarge/Getty Images)
Elihu Root first served as secretary of war at the 20th century’s turn, but then won renown as secretary of state for concluding treaties and convincing other nations to arbitrate disputes. (© Buyenlarge/Getty Images)

Two years before the assassination of Archduke Franz Ferdinand in Sarajevo, Bosnia ignited World War I, former Secretary of State and Senator Elihu Root won a Nobel Peace Prize for his determined efforts to convince states to resolve disputes by arbitration instead of arms. Root negotiated arbitration treaties with 24 nations, helped France and Germany settle differences in Morocco, and resolved Alaska boundary and Atlantic fisheries disputes with Canada.

Treaty of Portsmouth (1905)

Vintage postcard labeled 'The Portsmouth Drama' (© Buyenlarge/Getty Images)
President Theodore Roosevelt (center) in a postcard celebrating the 1905 Portsmouth Peace Treaty that ended the Russo-Japanese War (© Buyenlarge/Getty Images)

President Theodore Roosevelt won a Nobel Peace Prize in 1906 for his role in bringing the Russo-Japanese war of 1904–1905 to an end. The two countries battled on land and sea over control of parts of Manchuria, Korea and Sakhalin Island. The disputants met at a naval station in Portsmouth, New Hampshire, at Roosevelt’s invitation to help bridge their differences.