During the early Renaissance period, there was nothing even remotely resembling a "Nation-state" in Europe. As another writer above has asserted correctly, the Turks were a problem. But, so too were the local nobles, who were constantly warring, using mercenaries when necessary, robbing and pillaging for booty and sport. Success in overland trade was totally hit or miss, thus the attempts via sea to trade; which over time became vulnerable to piracy. Just a messy hodge-podge all around.
