Much of the Torlak-speaking Roman Catholic Krashovani who today form a part of the Croatian minority in Romania had declared themselves Bulgarian during the rule of Austria-Hungary.
The old Bulgarian population—which existed in Romania by the time of the founding of the principality of Wallachia and the inclusion of Transylvania in the Hungarian Kingdom—was referred as Șchei.
[10][11] This word may have been used by Romanians to refer to all South Slavs,[12] but it has also been proposed that they used this ethnic identification to prevent the Ottomans from demanding the Wallachian authorities to return the refugees to their place of origin.
During the Migration Period, both the Slavs and the Bulgars crossed what is today Romania to settle in the plains south of the Danube, establishing the First Bulgarian Empire in the 7th century.
The Golden Age of Bulgarian culture under Simeon I exerted considerable influence on the empire's transdanubian possessions.
In the mid-19th century the cities of southern Romania such as Bucharest, Craiova, Galaţi and Brăila attracted many Bulgarian revolutionary and political émigrés, such as Sophronius of Vratsa, Petar Beron, Hristo Botev, Lyuben Karavelov, Georgi Rakovski, Panayot Hitov, Evlogi Georgiev and Hristo Georgievi.
According to one estimate, the Bulgarian-originating population of the Romanian Old Kingdom and Transylvania (not including Bessarabia) by the time of the Liberation of Bulgaria in 1878 may have numbered up to one million.
Although set to be ceded to Bulgarian as per the Treaty of San Stefano, the region of Northern Dobruja was awarded to Romania by the Congress of Berlin of 1878.
Today, as an officially recognized ethnic minority, Bulgarians have one seat reserved in the Romanian Chamber of Deputies.