Final answer:
The duumviri were Roman magistrates who undertook various responsibilities, such as managing public building projects. In Pompeii, duumviri like Gaius Quinctius Valgus and Marcus Porcius funded and oversaw the construction of the amphitheater.
Step-by-step explanation:
The duumviri were Roman magistrates responsible for various tasks depending on their specific roles. In the context of the ancient Roman colony of Pompeii, for instance, the quinquennial duumvirs were involved in public building projects, such as the construction of the amphitheater, and they provided such facilities to the colonists in perpetuity. This can be seen in the inscription from Pompeii mentioning Gaius Quinctius Valgus and Marcus Porcius as duumvirs who funded the amphitheater for the honor of the colony. The title 'duumvir' literally means 'two men,' and it represents a shared office where two individuals are chosen to fulfill certain duties, which could range from administrative to religious functions in different regions of Rome and its colonies.