Few but
At the age of twenty-four, by a lucky chance, Columbus was thrown into Lisbon, center of European oceanic enterprise. There, he conceived the great enterprise that few but a sailor would have planned, and none but a sailor could have executed. His idea was to reach "The Indias".
1.What does "thrown into" mean?
2.What does "few but", "none but" mean?"Thrown into." He was in the city with little preparation, orientation. Just thrown in to sink or swim.
It's possible that a non-sailor could have conceived the plan but it would have been unusual. Only a sailor could have actually executed the plan.
"But" means "except" in contexts like that. Few persons except a sailor. No person except a sailor.