My American relations stem on one branch of the tree from one Henry Morrison Flagler. He is famous in the Florida area for having built the railroad network throughout Florida. Apparently he was a business associate of the Rockefellers. If you go to Florida, you will see a proliferation of the Flagler name. There is even a Flagler Beach. They did a profile of him on Biography recently that I saw.
The Breakers Hotel in West Palm Beach was built by him as a courtship gift to his second wife.
Apparently he wasn't very popular with the workers building the railroad, as he pushed them to finish the project, even through hurricane seasons. I think I heard that some died in its completion. Eventually, his dream came to fruition, but the original railroad structure collapsed during yet another hurricane season some few years later, and the whole catastrophe was dubbed "Flagler's Folly", and he was ridiculed by some.
Possibly that is even what caused the name change in your line ?