Final answer:
The Colosseum in Rome and the Basilica Nova with the Colossus of Constantine are examples of art and architecture used to legitimize rule and authority.
Step-by-step explanation:
One example of a piece of art or architecture used to legitimize rule is the Colosseum in Rome. Built in the 1st century CE, the Colosseum served not only as an arena for entertainment but also as a demonstration of Roman engineering prowess and the grandeur of the Roman Empire, effectively legitimizing the authority of the emperors who oversaw its construction and use. Similarly, the Basilica Nova and the Colossus of Constantine, with its overwhelming expression of imperial power, and the Triumphal Arches, both served ornamental and propaganda purposes, reinforcing the ruler's authority.