Silver, 3.25 grams, 17.82 mm. Spring – Summer 42 BC. Obverse: L SESTI PRO Q; veiled and draped bust of Libertas facing right. Reverse: tripod between axe and simpulum; Q CAEPIO BRVTVS PRO COS. RRC 502/2; RSC 11; RCV 143. Good fine for issue.

When Caesar returned to Rome as dictator after the final defeat of the Republican faction in the battle of Munda 45 B.C., Decimus Brutus joined the conspiracy against him after being convinced by Marcus Brutus. However, Caesar continued to trust in Decimus Brutus and even mentioned him in his will.

In 44 BC, he was made praetor peregrinus by personal appointment of Caesar and was destined to be the governor of Cisalpine Gaul in the following year.

On the Ides of March 15, when Caesar decided not to attend the Senate meeting due to the concerns of his wife, Calpurnia, Decimus Brutus persuaded him to go, dismissing Calpurnia's concerns. When Caesar arrived in Pompey's theatre for the senate meeting, Decimus and the rest of the conspirators attacked and assassinated him. According to Nicolaus of Damascus, Decimus Brutus was the third to strike Caesar, stabbing him in the side.