Pax Romana
In Western culture, when we think of Empire, thoughts of Rome dominate. More than 1,500 years after its empire collapsed, Rome is still with us: in our language, our architecture, in our dominant form of Christianity, in our popular imagination.

Pax Britannica

As the age of American Global power was dawning, the sun was setting on the British Empire.

Read from the BBC:
History of the British Empire.