Thracians
The Thracians were an Indo-European people, inhabitants of Thrace and adjacent lands (present-day Bulgaria, northeastern Greece, European Turkey, eastern Serbia and Macedonia).
They spoke the Thracian language. As non-Greek speakers, they were viewed as barbarians by the Greeks. From references in ancient sources, the Thracians seem to have been of fairer complexion than most ancient Greeks, and tended towards lighter hair and eyes. Recent archeological findings suggest Tracian men were about 190-200 cm of height, which is by far taller than the average Mediterraneans of that age.
In the Neolithic ages, Thracians inhabited an area from Northern Greece up to the Danube, the northern parts of Asia Minor, Boiotia, and Evoia. Even as far back as the Neolithic age the area of Thracian inhabitance seems to have extended north of the Danube into Romania, Moldova, parts of the Ukraine, and part of Pannonia.
In the 7th millennia B.C., Thracians occupied the area between northern Greece and southern Russia. According to ancient Greek historian Herodotus, Thracians were the second most numerous people after the people of India.
Josephus claims the founder of the Thracians was the biblical character Tiras, son of Japheth. "Thiras also called those whom he ruled over Thirasians; but the Greeks changed the name into Thracians.", AotJ I:6. This of course is mere legend, and probably bears no relation to reality.
The Thracians and Mycenaeans belonged to the same group from Europe originally. They split: the Mycenaeans settled in Greece and the Thracians settled in Thrace.
In the Illiad, the Thracians agreed to fight on the side of the Mycenaean Greeks in the Trojan War. According to Homer, the Thracians did not fulfill this promise. In the Odyssey, Odysseus and his men raided Thrace on their way back home from the war. This was to punish them for their "cowardice", as the Odyssey puts it. The actual reason why the Thracians declined to join the campaign is unknown (perhaps economic reasons, perhaps subsequent alliances).
Many mythical figures, such as god Dionysus, princess Europe and the hero Orpheus were borrowed by the Greeks from their Thracian neighbours.
Famous Thracians
Orpheus, in Greek legend, was the chief representative of the art of song and playing the lyre, and of great importance in the religious history of Greece.
Spartacus was a Thracian enslaved by the Romans, who led a large slave uprising in what is now Italy in (73 - 71 B.C.). His army of escaped gladiators and slaves defeated several Roman legions in what is known as the "Third Servile War".
(Wikipedia)