Illegal act of violence, detention, or plunder committed for private ends by the crew of a private ship (usually) against another ship on the high seas. Air piracy (i.e., the hijacking of an aircraft) is a more recent phenomenon. Piracy has occurred in all stages of history: the Phoenicians, Greeks, and Romans engaged in it, as did the Vikings, Moors, and other Europeans. It also occurred among Asian peoples. During the wars between England and Spain in the late 16th century, treasure-laden Spanish galleons proceeding from Mexico into the Caribbean were a natural target for pirates. In the 16th–18th centuries pirates from North Africa's Barbary Coast threatened commerce in the Mediterranean. The increased size of merchant vessels, improved naval patrolling, and recognition by governments of piracy as an international offense led to its decline in the late 19th century. In the late 20th century incidents of piracy occurred with increasing frequency in the seas of East and Southeast Asia. See alsoBlackbeard; Francis Drake; Jean Laffite; Henry Morgan.