Pirates became a problem. Driven from the Caribbean by the Royal Navy, many took to hiding among the coasts of North and South Carolina, which is filled with barrier islands. In June 1718 four pirate ships began a blockade of Charleston harbor. Their captain was none other then Edward Teach, better know to history as Blackbeard. He captured several prominent citizens of Charleston, raided up to nine ships, and refused to leave and release his prisoners until receiving a chest of medicine that was possibly used to treat sexually transmitted diseases.