A United States diplomatic representative to Romania has existed since 1880. The United States formally recognized Romania in 1878, following the Treaty of Berlin; diplomatic relations were opened in 1880, and American diplomats were sent to the country. Until the early 20th century, most ambassadors to Romania were also responsible for Greece, Serbia, and occasionally Bulgaria. No US Embassy was established in Romania for some time; ambassadors typically operated out of Athens until about 1905, at which point an embassy was established in Bucharest.