Final answer:
Francis Scott Key was trying to negotiate the release of American prisoner William Beanes right before the Battle of Baltimore. However, he was held captive on a British ship during the bombardment of Fort McHenry.
Step-by-step explanation:
Francis Scott Key was trying to negotiate the release of American prisoner William Beanes right before the Battle of Baltimore. Key, being a lawyer, was chosen to go with the American negotiators to meet with the British fleet anchored in the Chesapeake Bay. However, once they arrived, the British refused to release Beanes, and Key was held captive on one of their ships during the bombardment of Fort McHenry.