I didn't answer your other inquiry. The construction of the Brimstone Hill Fortress began in 1690 and it continued intermittently for just over 100 years until completion.
I had thought it was continuous, but apparently not. It was hard to find anything other than it was 100 years in the making. But, I didn't look too hard after I saw that a dozen times. :)
Maybe they had to stop in between attacks and battles...
You know what? I never even thought about that, but it makes a lot of sense!