Okay, per Wikipedia: “Longfellow was inspired to write the poem after visiting the Old North Church and climbing its tower on April 5, 1860.” So it was the lanterns.
In addition: “Longfellow's family had a connection to the historical Paul Revere. His maternal grandfather, Peleg Wadsworth, was Revere's commander on the Penobscot Expedition.”
Really, @Lucy?!?! I could ask that or start asking myself, 'Where in The World is Lee Jordan?' or 'Where in The World are Zack and Ivy?' I mean no one knows where everybody us at.