They’ve been described as “noble heroes” by sympathetic Somalis, denounced as criminals by critics. But the word most used to describe the men holding an American captain off the Horn of Africa is “pirates” — conjuring images of sword-wielding swashbucklers romanticized by Hollywood.

The 21st-century reality, though, is a far cry from that.

Instead: A vigilante movement that years ago tried to defend Somali shores morphed into a full-blown pirate scourge — after fishermen on defense stumbled upon an astoundingly lucrative bounty waiting to be had on their doorstep: around 25,000 ships, most unarmed, transiting the Gulf of Aden each year.

Picture ragged Somali fishermen armed with rocket launchers, GPS systems and satellite phones. Picture tiny skiffs cruising the coast of a war-infested nation crawling with gunmen. Picture bandits with sunglasses in worn shirts firing machine-guns at cruise ships, scampering aboard captured trawlers with crude ladders. And most of all, picture ransoms — huge ransoms.

The plight of an American captain, seized from the U.S.-flagged Maersk Alabama and held by Somali pirates since Wednesday on a drifting lifeboat out of fuel, is only one of the latest examples of a problem that has plagued the region for years. The modern piracy scourge in the Horn of Africa arose from the ashes of Somalia’s government, overthrown in 1991. Somali pirates are reportedly holding about a dozen ships with more than 200 crew members.

Capt. Richard Phillips, of Vermont, is believed to have been the first U.S. citizen taken by pirates since 1804, when U.S. Navy Commodore Stephen Decatur battled the infamous Barbary pirates off the northern coast of what is now Libya, dispatching U.S. Marines to the shores of Tripoli.