The Dacians were the ancient Indo-European inhabitants of the cultural region of Dacia, located in the area near the Carpathian Mountains and west of the Black Sea. They are often considered a subgroup of the Thracians. This area includes mainly 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 and the related Getae spoke the Dacian language, which has a debated relationship with the neighbouring Thracian language and may be a subgroup of it. Dacians were somewhat culturally influenced by the neighbouring Scythians and by the Celtic invaders of the 4th century BC.