Short answers, pulled from the story.
The Roman province of Macedonia was formally established in 148 BC, after the general Quintus Caecilius Metellus defeated the pretender Andriscus near Pydna in the Fourth Macedonian War. It was Rome's fifth permanent province, the first added since two Spanish provinces were created in 197 BC.
The Via Egnatia was a Roman road initiated by Gnaeus Egnatius after 146 BC, running from Dyrrhachium on the Adriatic coast through Macedonia to Thessalonica and east to the Hebrus river. It provided the main overland link between Rome and its eastern Mediterranean domains, and its main stretch was completed by 120 BC.
Two decisive civil war battles were fought in Macedonia: the Battle of Pharsalus in August 48 BC, where Caesar defeated Pompey, and the Battle of Philippi in 42 BC, where Mark Antony and Octavian defeated Brutus. Pompey had retreated to Macedonia with five legions and around two hundred senators had set up a Senate in exile at Thessalonica.
Macedonia was a senatorial province governed by a proconsul for most of the Imperial period, meaning it was administered by senators rather than by imperial legates. Emperor Tiberius briefly converted it to an imperial province in AD 15, but Claudius restored its senatorial status in AD 44.
Six Roman colonies were established in Macedonia during the Triumviral period: Cassandrea, Philippi (formally Colonia Iulia Augusta Philippensis), Dium, Pella, Byllis, and Dyrrhachium. These were settled with veterans who held Roman citizenship, while local inhabitants did not receive citizenship of the new colonies.
Under the reforms of Diocletian around AD 293, the province was divided into smaller units including Macedonia Prima, Macedonia Secunda (or Salutaris), Thessalia, and Epirus Nova. The region became part of the Diocese of Macedonia administered from Thessaloniki, and after 395 passed permanently to the Eastern Roman Empire, continuing as such until the end of the fourteenth century.