Institutio Oratoria

With regard to this class of case Celsus points out that they cannot actually occur in the courts, a fact which I imagine is familiar to all: for the jury is empanelled to try one accused person only, and even though the defence and the prosecution may accuse each other of tile crime, the first case must be tried before the second.

Apollodorus again stated that mutual accusation involved two separate disputes, and this is of course in conformity with the practice of the courts, which insists on two separate trials. On the other hand, mutual accusation is possible in cases tried before the senate or the emperor, and even in the courts the fact of mutual accusation will involve