Under the principate their status underwent a marked decline.
Henderson, The Life and Principate of the Emperor Nero (1903); also article Nero.
2 Save for the title of dictator, which undoubtedly carried unpopular associations and was formally abolished on the proposal 9f Antony after Caesar's death, this cumulation of powers has little to distinguish it from the Principate of Augustus; and the assumption of the perpetual dictatorship would hardly by itself suffice to account for the murder of Caesar.
The incorporation of existing towns, hitherto non-Roman, in the uniform municipal system of the principate took place mainly in the eastern part of the Empire, where Greek civilization had long fostered urban life.
At any rate by the end of the 1st century of the principate municipia are numerous in the western as well as the eastern half of the Empire, and the towns are everywhere centres of Roman influence.