Invictus: Latin for Unconquered

I was reading an interview of David Murdock, owner of the Dole Food Company and Castle & Cook. He is 85 years of age and was recently featured in one of Costco's periodic magazine to its members. The interview ends with uplifting lines narrated by Mr. Murdock. This is amongst his favorite poems - Invictus - Latin for 'unconquered' - by 19th century British Poet William Ernest.

It matters not how strait the gate,
How charged with punishments the scroll,
I am the master of my fate:
I am the captain of my soul.