I'm looking for a word or phrase similar to "opus magnum" or "masterpiece", but refering instead to a period of time in which a scholar or artist made their greatest achievements.
For example:
Mozart held a variety of positions throughout his life, but many consider his time spent in Vienna to be his xxxxx.
Edit:
Thanks for all the great answers so far! To give a bit of context, I'm writing a thesis about atomic clocks and I want to make the following simile:
If timekeeping was born in Egypt 8000 years ago and 1955 was its coming of age, we may today be witnessing its xxxxx.
Initially I was thinking "renaissance" but it didn't quite work with the simile, hence this question. So far I think "prime" and "heyday" fit best.