Plovdiv reached an agreement that the Principality of Bulgaria and Eastern Rumelia had a common government, Parliament, administration, and army. Today 6 September is celebrated as the Unification Day and the Day of Plovdiv. After the unification, Plovdiv remained the second most populous city in Bulgaria after the capital Sofia. The first railway in the city was built in 1874 connecting it with the Ottoman capital, and in 1888, it was linked with Sofia. In 1892 Plovdiv became host of the First Bulgarian Fair with international participation which was succeeded by the International Fair Plovdiv. After the liberation, the first brewery
Plovdiv institution outside the United States, the American College of Sofia, was founded in Plovdiv in 1860 and later moved to Sofia. On 5 September 2014, Plovdiv was selected as the Bulgarian host of the European Capital of Culture 2019. This happened with the help of the Municipal Foundation "Plovdiv 2019″, a non-government organization, which was established in 2011 by Plovdiv's City Council whose main objectives were to develop and to prepare Plovdiv's bid book for European Capital of Culture in 2019. Plovdiv was given various names throughout its long history. The Odrysian capital "Odryssa" () is suggested to have been