“He makes a solitude, and calls it - peace.”

and so describes mental illness, prison, a contented slave, etc.

This is a literary allusion to Tacitus' well-known irony: "To rob, to ravage, to murder, in their imposing language, are the arts of civil policy. When they have made the world a solitude, they call it peace." [Auferre, trucidare, rapere, falsis nominibus imperium, atque, ubi solitudinem faciunt, pacem appellant. ]

Something to worry about when the powers-that-be say they are fighting for 'world peace.'

Oh to know latin...Byron defines the fear of living in a reality that defies diversity, complexity, multiplicity-anything can seem an ideal when language itself is so distorted.