1006
The brightest supernova ever recorded, SN 1006, is observed in the
constellation of Lupus. SN 1006 was a supernova, widely seen on Earth
beginning in the year 1006 AD. It was the highest relative magnitude stellar
event in recorded history and clearly viewable from Earth in the
pre-telescopic era.
It's gaseous remains here photographed almost 1000 years later, what a
shame it wasn't 1006 years later.
Read more here:
http://en.wikipedia.org/wiki/SN_1006