Before the lex Calpurnia, criminal cases were investigated by ad-hoc courts before one of the legislative assemblies, which were subject to emotion and rhetorical devices. Instead, the permanent court created by this law was presided by a praetor with a jury composed of senators, who therefore had to judge their peers. It appears that the scope and the penalty were very limited, as officials could only be sued for extortion, and they could only be forced to give back what they had stolen, without additional compensation. Moreover, provincial claimants had to be represented by a Roman patron at the court. Considering the restrictions of the lex Calpurnia and the fact that its author was a conservative, it has been suggested that Piso actually wanted to reinforce the powers of the Senate over the assemblies and the tribunes of the plebs.
