Marcus Junius Pera

Marcus Junius Pera (fl. 230216 BC) was a Roman politician during the Second Punic War.
Career.
Pera is first recorded as holding office when he was elected as one of the consuls for the year 230 BC. During his time in office he, along with his colleague Marcus Aemilius Barbula, campaigned against local tribes in Liguria.
He then began an 18-month term as censor in 225 BC, during which he and his colleague, Gaius Claudius Centho, conducted a census of the Roman population. Livy reports the number of citizens as being 270,212 in the census of the time. Such a large number would prove essential in Second Punic War.
Dictatorship.
During Hannibal's invasion of Italy during the Second Punic War, the Carthaginian general all but wiped out an 85,000-strong Roman army at the Battle of Cannae in 216 BC. In doing so, one consul, Lucius Aemilius Paullus, was killed and the other, Gaius Terentius Varro, was stranded with the few survivors of the battle at Venusia.
Without the consuls as military commanders, a dictator was required to fill the gap at the top of the command structure. Pera was appointed with Tiberius Sempronius Gracchus as his "magister equitum". He immediately instituted a levy to replace the men killed at Cannae. With up to a fifth of adult male citizens already lost to the war, Pera was forced to enlist underage boys and even buy and arm 8000 slaves. By doing so, he had created a citizen army of four legions, reinforced by the slave-force and contributions from remaining allies.
He fought no pitched battle against Hannibal during his time in command, instead leaving Gracchus to relieve the Romans besieged at Casilinum. Though Zonaras reports Pera as being wrong-footed by the Carthaginian as he was shadowing his camp. After ordering his men to copy the schedules of the Carthaginians - and thus not be taken by surprise - Pera was attacked by a detachment of Hannibal's army. When his troops had repulsed the offensive and retired, assuming the Carthaginians would now rest, he was surprised by a second attack from the bulk of the Carthaginian force that Hannibal had kept in reserve. The Roman entrenchments were captured.
His dictatorship is also notable for the concurrent appointment of Marcus Fabius Buteo. It marked the only occasion in Roman history where two dictators were in office at the same time. With Pera away on campaign, Buteo was selected to appoint new men to the Senate after its ranks had been diminished greatly at Cannae. According to Livy, Buteo was uncomfortable with the unprecedented dual-dictatorship and resigned promptly on completing his task.