Year 447 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Macerinus and Iullus (or, less frequently, year 307 Ab urbe condita). The denomination 447 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.
Pericles leads Athenian forces in the expulsion of barbarians from the Thracian peninsula of Gallipoli, in order to establish Athenian colonists in the region. Thus Pericles starts a policy of kleruchos or "out-settlements". This is a form of colonisation where poor and unemployed people are assisted to emigrate to new regions.