Okay, confirmed now (page 10). Blackthorne was the first English pilot to sail through the strait of Magellan.
Not that anybody probably care at this point. I just confused the heck out of myself.
IIRC, Blackthorne wasn't taking advantage of the women sent to him.
Probably the book, but the Japanese attending/guarding him suggested offering him a duck or a young boy instead.
Maybe the series. Been a while.