Year 3 was a common year starting on Monday (link will display the full calendar) of the Julian calendar.
The rule of Augustus is renewed for a ten-year period.
Augustus adopts his grandson, Gaius Caesar, with the expectation that he will succeed him. Gaius is made proconsul and is sent on a special mission to the East.
Lucius Aelius Lamia and Marcus Valerius Messalla Messallinus are consuls of Rome.
Menneas becomes Archon of Athens.
Five German tribes are unified by Marbod, King of the Marcomanni. The unification of the five tribes represents a direct threat to Rome in the area that will become Silesia and Saxony.
Wang Mang foils a plot by his son, Wang Yu, his brother-in-law, Lu Kuan, and the Wei clan to oust him from the regent's position. Wang Yu and Lu Kuan are killed in the purge that follows.
King Yuri of Goguryeo moved the capital from Jolbon Fortress to Gungnae Fortress.
Ban Biao, Chi