Year 178 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Brutus and Vulso (or, less frequently, year 576 Ab urbe condita). The denomination 178 BC for this year has been used since the early medieval period, when the Anno Dominicalendar era became the prevalent method in Europe for naming years.
One of Perseus' first acts on becoming king of Macedonia is to renew the treaty between Macedonia and Rome. In the mean time, Perseus builds up the Macedonian army and puts out feelers for creating an alliance with the Greek leagues, with his northern barbarian neighbours, and also with the Seleucid king Seleucus IV.