Suetonius

Gaius Suetonius Tranquillus was a Roman scholar and official who served as secretary to the emperor Hadrian. His Lives of the Caesars, twelve biographies from Julius Caesar to Domitian, strongly shaped how later ages pictured imperial Rome. Suetonius arranged each life by topic rather than strict chronology and included gossip, omens and personal details that other historians left out.

In his Life of Julius (chapter 88) he reports that during the games held in Caesar's honor after the assassination of 44 BCE, a comet shone for seven successive days, and people believed it was Caesar's soul received into heaven. The comet, the sidus Iulium, was used by Augustus in his own propaganda. Chinese court astronomers also recorded a comet in the same year, which makes it a useful cross-check between Roman and Chinese records.