Why is the constituonalism?

What is nerva the Roman Emperor known for?

Nerva was a Roman Emperor who briefly ruled for less than two years. He ascended to throne at the age of 65.Although his rule was marred by financial difficulties and struggle for power with Roman army, he is credited for ensuring peaceful transition of power after his death. He also tried to restore liberties which were curtailed during previous autocratic governments. He is remembered as a wise and just ruler.