[2] The United States and Bulgaria agreed to resume diplomatic relations on March 24, 1959[3] after the Bulgarian authorities had issued a formal apology in the Heath case.

The American Consul General in Istanbul, Eugene Schuyler, traveled to the Bulgarian territories of the Ottoman Empire in July and August 1876 to investigate the reports of atrocities and massacres.

[6] In November 1876, Consul General Schuyler and Prince Tseretelev published their full report, estimating that fifteen thousand Bulgarians had been killed in the aftermath of the uprising.

The Bulgarian writer Aleko Konstantinov visited the exposition and wrote a book, To Chicago and Back, in which he presented America as a technological leader and a land of opportunity.

Finally, on September 19, 1903, John B. Jackson, U.S. Special Envoy and Minister Plenipotentiary to Greece, Romania and Serbia, presented his diplomatic credentials and his accreditation letter from U.S. President Theodore Roosevelt to Prince Ferdinand.

At his Palace in Sofia, Prince Ferdinand gave a toast to President Roosevelt in English, and a band played American music, but the U.S. still did not fully recognize Bulgaria as an independent nation, since it was still by treaty a principality under Ottoman sovereignty.

The United States wished to stay out of any European conflict, while Bulgaria wanted to see which side, the Entente or the Central Powers, would help it regain Thrace, Dobrudzha, and Macedonia.

On December 22, 1914, Stefan Panaretov, a former professor from Robert College in Istanbul, presented his credentials to President Wilson in Washington, and became the first Bulgarian Ambassador to the United States.

[8] When British forces came close to capturing the Dardanelles and Istanbul in the spring of 1915, Bulgaria considered joining the Entente, but Britain, France and Russia were not willing to take territory away from their allies, Romania, Serbia and Greece.

The Bulgarian prime minister, Radoslavov, summoned U.S. Consul Dominick Murphy and assured him that Bulgaria was anxious to maintain good relations with the United States.

Despite opposition from King Ferdinand, The Bulgarian Government of Prime Minister Malinov approached American diplomats about a possible withdrawal from the War, accepting the principals laid by President Wilson.

The Commission concluded: "(1) that the area of annexed by Romania in the Dorbrudja is almost surely Bulgarian in character and should be returned; (2) that the boundary between Bulgaria Turkey should be restored to the Enos-Midia line as agreed upon at the conference in London; (3) that the south border of Bulgaria should be the coast of the Aegean Sea from Enos to the Gulf of Orfano, and should leave the mouth of the Struma River in Bulgarian territory;[8] (4) that the best access to the sea for Serbia is through Saloniki; (5) that the final disposition of Macedonia cannot be determined without further inquiry; (6) that an independent Albania is almost certainly an indesirable political entity.

By the time the final peace treaty between the Allies and Bulgaria was negotiated, President Wilson had returned to the United States, where he faced bitter opposition to his proposed League of Nations within the U.S. Senate.

The Communist Party or its allies made two attempts to kill King Boris, including a bombing of St. Nedelya Cathedral in 1925 which resulted in the death of 123 people.

Pursuing its policy of isolationism, the United States played little role in the political events of the Balkans, but it did move toward more constructing more normal diplomatic relations with the changing Bulgarian governments.

The Rockefeller Foundation spent about three hundred thousand dollars in Bulgaria, sending thirty doctors to study in the United States, sharing the cost of establishing a National Health Institute, and carrying out a major campaign to eradicate malaria.

In March 1941, the German Army asked permission to move its troops through Bulgaria to attack Greece, which was successfully resisting an invasion by Germany's ally, Italy.

On 20 April 1941, Bulgarian forces entered Greece on the heels of the Wehrmacht without fighting and went on to occupy the territories of the present-day region of Eastern Macedonia and Thrace, except for the Evros prefecture, up to the Aegean Coast, including the islands of Thasos and Samothrace.

On August 1, 1943, One hundred and seventy-seven B-24 Liberators with 1,726 crew members took off from Libya with the destination of the Ploiești refinery complex in Romania, which was reported to be producing sixty percent of the gasoline and petroleum products used by the German war effort.

Between 1943 and 1944, 329 Allied pilots and air crew from seven nations, mostly American, were captured and confined in a prisoner-of-war camp located within the boundaries of what is today the Shumensko Plateau Natural Park, near the city of Shumen.

As the Red Army approached the northern border of Bulgaria in September 1944, the Bulgarian government announced that it was withdrawing unilaterally from the Axis, withdrew its troops from Greece and Yugoslavia, and then declared war on Germany, hoping to avoid a Soviet occupation.

By the time that Joseph Stalin, Winston Churchill and President Roosevelt met in Yalta in March 1945, Bulgaria was occupied by the Soviet Army, and a pro-Soviet government had been installed.

The announcement by President Harry S. Truman in 1947 of the policy, under which the United States would support the Greek Government against Communist rebels backed by Yugoslav dictator Josip Broz Tito, further increased tensions in the region.

A purge was launched against suspected "Titoists" in the Bulgarian Government, leading to removal of between 60,000 and 70,000 Communist Party members, and to the arrest, trial and execution in December 1949 of Deputy Prime Minister Traicho Kostov.

In March 1954 it found a forty-one-year-old politburo member, Todor Zhivkov, who had commanded the People's Militia in Sofia at the end of World War II.

Zhivkov modified some Stalinist policies, officially "regretting" the trial and execution of Kostov and other alleged "Titoists," and closing some labor camps, but the regime continued to harshly repress any signs of dissent.

Zhivkov maintained a strict and repressive Soviet-style regime at home, but he also tried, following the lead of Soviet leader Nikita Khrushchev, to build better relations with the United States.

The rise of democratic movements across Eastern Europe in the 1980s, the arrival in power in Moscow of Mikhail Gorbachev in 1985, and the fall of the Berlin Wall in 1989, led to the downfall of Todor Zhivkov, who resigned as Communist Party leader on November 10, 1989.

Peace Corps Volunteers began to arrive in Bulgaria to teach English and aid in community development, and a Fulbright Program Commission was created to establish university exchanges.

The BBC reported on May 1, 1999 that "the Bulgarian public is divided between a desire to join NATO and the European Union and sympathy for fellow Slavs and Christian Orthodox Serbs."