Who are the ‘five good emperors' and why are they considered good?

Nerva: helped restore normalcy after the assassination of Domitian, Tajan: expanded the borders of Rome to their peak, built several public buildings and shared the prosperity of his military conquests with the roman people , Hadrian: was a scholar and concerned with leading a good life rather than clinging to power, Antoninus Pius: his particular on making the law more equitable and fair earned him a reputation as an exceedingly just man,& Marcus Aurelius: included the senate in his decision making and had a reputation of trying to not expand the power of the emperor