in (one's) pomp
At the peak of one's skill or physical ability; in one's most successful or productive period. Primarily heard in UK. In its pomp, the company developed some of the most influential video games of all times. I used to be able to bench press twice as much when I was in my pomp. When they were in their pomp, the team was almost untouchable on the pitch.
in your pomp
in your period of greatest effectiveness; in your prime.