An important early result of the contact between the two regions was the adoption of the Cyrillic script, which was developed during the 9th century AD at the Preslav Literary School in the First Bulgarian Empire during the reign of Tsar Simeon I the Great.

[3] At the closing of the 18th century, larger scale settlement of Bulgarians in Russian-controlled Ukraine continued, and particularly significant waves of emigration began after the Russo-Turkish Wars of 1806–1812 and 1828–1829.

In 1856, after the Treaty of Paris, the region of Bessarabia (south-west to present-day Ukraine) was divided with the southwestern parts, including Bolhrad, Izmail and Kiliia, incorporated into Moldova (since 1861 – Kingdom of Romania), and the northeastern ones, centered on Comrat, remaining in the Russian Empire.

Many people who would subsequently hold political office in Bulgaria received much of their education in Russian-controlled Ukraine: for example, Todor Burmov, the first Bulgarian Prime Minister was a graduate of the Kyiv Theological Academy.

[7] This mutual recognition did not, however, last long, as by this point Bulgaria was still involved in the war with the German Empire, whose preoccupations with Ukraine took precedence and led to the failure of developing robust trade relations.

[8] On 24 September 1918, following the Bulgarian collapse at the Vardar offensive, Bulgaria signed the armistice of Salonica, ending its participation in World War I.

Bulgaria refused to open official diplomatic channels with the Soviet Union until the 1930s,[10] and thus Bulgarian and Ukrainian contacts ceased.

By 1944, however, the Axis had suffered major setbacks and following the defection of Romania, Soviet forces arrived at the Bulgarian border and began occupying the country.

In November 1989 the Communist regime in Bulgaria was overthrown,[11] and two years later, following the Belovezha Accords, the Soviet Union was dissolved and Ukraine became once again an independent country in December 1991.

[15] Bulgaria became a critical supplier of diesel, weapons and ammunition to Ukraine in the early stages of the war, and Bulgaria took a leading role in the imposition of sanctions against Russia on the initiative of Prime Minister Petkov and Finance Minister Asen Vasilev during a meeting with other EU delegates.