HistoryIn 306 BC, Lysimachus became the ruler of Thrace in the aftermath of the breakup of the Macedonian Empire, the large empire built by Alexander the Great that stretched from the Balkans and Egypt to the Indus River and China. Thrace was initially a confederation of Odrysian tribes, but it became the first Hellenized country, with its upper classes wearing Greek clothing and speaking in Ancient Greek. The Kingdom of Thrace's capital was Tylis.
Under Lysimachus, Thrace was a part of the Wars of the Diadochi, a competition between the successor states of Alexander's empire. They allied with the Ptolemaic Empire (Egypt) and Seleucid Empire against the Antigonid Empire in 301 BC and defeated Antigonus One-Eye at the Battle of Ipsus, but the alliance was dissolved soon after as the Diadochi ("successors") scrapped over control of Alexander's lands. In 281 BC Lysimachus was killed at the Battle of Corupedium by the army of Seleucus, but when Seleucus crossed the Hellespont to claim the throne of Thrace, he was assassinated by Ptolemy Keraunos. Thrace and Macedon became independent, with the Antigonids ruling over Greece and Macedonia while the Thracians continued to rule over Bulgaria.
The Thracians formed an alliance with the Roman Republic in the mid-200s BC, as the Romans were at war with Macedon. The Romans conquered Macedon in 168 BC after the Battle of Pydna, and Thrace became a satellite nation of Rome. In 46 AD, it was incorporated into the Roman Empire as a province, and the transition was swift.