The Dacians (; , ) were an Indo-European people, part of or related to the Thracians. Dacians were the ancient inhabitants of Dacia, located in the area in and around the Carpathian Mountains and west of the Black Sea. This area includes the present-day countries of Romania and Moldova, as well as parts of Ukraine, Eastern Serbia, Northern Bulgaria, Slovakia, Hungary and Southern Poland. The Dacians spoke the Dacian language, believed to have been closely related to Thracian, but were somewhat culturally influenced by the neighbouring Scythians and by the Celtic invaders of the 4th century BC.