the prime of life

the prime of life

One's happiest, most successful time; the period when one has the most energy, vitality, and potential. Often structured as "the prime of (one's) life." My father was in the prime of life when he was diagnosed with cancer. It's many a man and woman who, in old age, looks back on the prime of their lives with bittersweet nostalgia.
See also: life, of, prime
Farlex Dictionary of Idioms.

prime of life

The best years of one's life, when one is at the peak of one's powers, as in She was in the prime of life when she began to lose her sight. The related phrase in one's prime can be applied to objects as well as persons. For example, The roses were in their prime when you last saw them. In both idioms prime means "first in quality or character." [Early 1700s] Also see past one's prime.
See also: life, of, prime
The American Heritage® Dictionary of Idioms by Christine Ammer.

prime of life, the

The best years of one’s life, at the peak of one’s powers. The idea that there should be a particular time of flourishing is an ancient one. Plato in The Republic defined it as a period of about twenty years in a woman’s life and thirty in a man’s. Poets, among them Robert Herrick and John Milton, generally equated one’s youth with one’s prime. However, the eccentric schoolteacher-heroine of Muriel Spark’s novel The Prime of Miss Jean Brodie (and the 1969 motion picture based on it) declared the years of her rapidly advancing middle age to be her prime.
See also: of, prime
The Dictionary of Clichés by Christine Ammer
See also:
  • prime of life
  • prime of life, the
  • in the prime of life
  • in (one's) prime
  • in prime
  • there's life in the old dog yet
  • a change of scenery
  • a change of scene
  • (one's) old man
  • (there's) no peace/rest for the wicked
References in classic literature
We were saying that the parents should be in the prime of life?
Republic
I pointed out to Miss Wendermott that you were in the prime of life and in magnificent condition, while her father was already on the threshold of the grave and drinking himself into a fever in a squalid hut in a village of swamps.
A Millionaire of Yesterday
You are barely in the prime of life, you are strong, you have the one thing which society today counts almost divine--great, immeasurable wealth!
The Malefactor
When this expression was upon him, he looked as if he were old; but when it was stirred and broken up--as it was now, in a moment, on his speaking to his daughter--he became a handsome man, not past the prime of life.
Tale Of Two Cities
Moreover, as I was still in the prime of life, it pleased me better to be up and doing.
Arabian Nights
He was in the prime of life, but very bald--had been in the army and the coal trade--wore very stiff collars and prodigiously long wristbands--seldom laughed, but talked with remarkable glibness, and was never known to lose his temper under the most aggravating circumstances of prison existence.
A Rogues Life
To his surprise there appeared, in her place, a perfect stranger to him-- a gentleman, in the prime of life, with a marked expression of pain and embarrassment on his handsome face.
The Haunted Hotel
Personally he was a handsome man, in the prime of life; and he was possessed of a sufficient income to marry on.
The Two Destinies
It is the fate of most men who mingle with the world, and attain even the prime of life, to make many real friends, and lose them in the course of nature.
The Posthumous Papers Of The Pickwick Club
I've known it long enough to lose my dread and be happy working for those I love, and don't call yourself old--forty is the prime of life. I couldn't help loving you if you were seventy!"
Little Women
This person proved, on her presenting herself, for judgment, at a house in Harley Street, that impressed her as vast and imposing--this prospective patron proved a gentleman, a bachelor in the prime of life, such a figure as had never risen, save in a dream or an old novel, before a fluttered, anxious girl out of a Hampshire vicarage.
Turn Of The Screw
It dwelt on my being young, and he past the prime of life; on his having attained a ripe age, while I was a child; on his writing to me with a silvered head, and knowing all this so well as to set it in full before me for mature deliberation.
Bleak House
They were male and female; babies, young boys and young girls; young married people, and some who had passed a shade beyond the prime of life. I refer to the "Adams Jaffa Colony." Others had deserted before.
The Innocents Abroad
This is what people who serve the Queen have to expect: to be shot out into the cold world to find a living just when they are beginning really to understand their work, and to reach the prime of life. I suppose they don't mind it, but for my own part I had rather earn my bread as a hunter.
King Solomons Mines
He felt himself a man undoubtedly in the prime of life. Pride glowed in his eye as he let the wind buffet him and stood firm.
The Voyage Out