Portugal
Portugal
Portugal
the Netherlands
because...
Caravel
It was the most effective sailing ship of the 15th Century
evidence of sailing was found in ancient Egypt but major technology did not exists until the 15th century in Europe.
It was Catholic
What was the effect of European exploration on global interactions in the fifteenth century
yuo
Oh, dude, the preeminent European maritime power in the fifteenth century was Portugal. They were all about sailing the high seas, discovering new lands, and probably getting seasick along the way. So yeah, Portugal was basically the cool kid on the block when it came to sailing back in the day.