President Roosevelt brokered the Portsmouth Peace Treaty, ending the war.
Source: J.F. Macdonald through Encyclopædia Britannica
After Japan and Russia exhausted their resources fighting the Russo-Japanese War, President Roosevelt was invited by Japan to broker the Portsmouth Peace Treaty, which balanced power in the Manchurian region.
Portraits of the Russian and Japanese Diplomats, and Theodore Roosevelt
Source: Library of Congress
The Japanese requested President Roosevelt to initiate peace talks. Roosevelt convinced the Russian Tsar Nicholas that peace would be of benefit for both sides. Sergei Witte of Russia and Jutaro Komura of Japan negotiated the terms of peace in Portsmouth, New Hampshire, assisted by Roosevelt's third secretary of state Herbert Pierce.
"Japanese and Russian peace delegates arriving at Portsmouth, N.H., 1905" (Silent Film)
Source: Library of Congress
Excerpts from the Treaty of Portsmouth (First Page, Articles 4-6, Last Page)
Source: Diplomatic Record Office of the Ministry of Foreign Affairs (Japan)
Source: Original text of the Portsmouth Peace Treaty
Territories before and after the treaty
Source: Mapworks
In return for not having to pay war reparations, Russia ceded half of Sakhalin island and the control over Korea, to Japan. Both sides withdrew from Manchuria, however, the Japanese maintained some influence. Subsequently, Japan annexed Korea and instated a puppet government.
Source: Original text of the Portsmouth Peace Treaty