A band worn round the leg to keep up a stocking highest order of English knighthood?

The band worn around the leg to keep up a stocking is called a "garter." The highest order of English knighthood associated with this is the Order of the Garter, founded in 1348 by King Edward III. This prestigious order is one of the oldest and most distinguished in the United Kingdom, honoring individuals for their service to the monarchy and the realm.