Old Glory is a common nickname for the flag of the United States, bestowed by William Driver, an early nineteenth century American sea captain.
However, it also refers specifically to the flag owned by Driver, which has become one of the U.S.'s most treasured historical artifacts.
The captain was very pleased with his gift, and kept it with him always. By most accounts, he first hailed the flag as "Old Glory," when he left harbor for a trip around the world in 1831-1832, as commander of the whaling vessel Charles Doggett. Old Glory served as the ship's official flag throughout the voyage. Some weathering and fraying almost certainly occurred during this severe service, and the flag shows evidence of patching on more than one occasion.
When the Civil War broke out and Tennessee seceded from the union in 1861, Driver knew or feared that the rebel government would attempt to destroy the locally famous Old Glory. He had the flag sewn inside a comforter to conceal it. One curious point, never explained, is that he seems to have had this done by some neighbor girls named Bailey, rather than by his own family. Accounts differ as to whether and how hard the Confederate authorities searched for the flag, but in any event it survived. When Union forces retook Nashville the following year, Driver was able to bring out his flag and hoist it from the state capitol spire, the last time it flew from a flagpole. A unit of Federal troops, the Sixth Ohio Regiment, was present, and adopted "Old Glory" as their motto. These dramatic events were reported by many newspapers, and Old Glory became nationally famous.