Definizione e Significato di "swan song"

What is the origin of the idiom "swan song" and when to use it?

The idiom "swan song" originates from the ancient belief, dating back to Greco-Roman mythology, that swans sing a beautiful, haunting melody just before their death. This belief was perpetuated in various literary works, including the Roman poet Virgil's writings. Over time, this expression evolved to describe a final, notable performance or effort before retiring, leaving a position, or coming to the end of a career.