Unit one annotated timeline by Patrick By mcadapat 146 End of Hellenistic Empire 206 End of Qin Empire 206 Start of Han Empire 220 End of Han Empire 221 Start of Qin Empire 224 End of Parthian Empire 247 Start of Parthian Empire 250 Ashokah preaches Buddhism 320 Start of Gupta Empire 321 Start of Maurya Empire 323 Start of Hellenistic Empire 476 End of Roman Empire 550 End of Gupta Empire Oct 18, 1927 Start of Roman Empire Oct 18, 2009 Contantine Issues Edict allowing Christianity Mar 2, 2022 End of Maurya Empire