Comet Halley 451 AD
Comet Halley was first seen by to Chinese astronomers on June 10th 451 in Perseus,it then moved through Leo passed Hercules and swept through Virgo and disappeared near Crater and Corvus. It was last seen on August 16th. In Europe it was between June 10th and August 1st.
Comets were often seen as profits of doom, and this appearance of Halley's comet was only 2 years before the death of Attila the Hun who had wrought such destruction to the Roman empire.