Ascending the Staircase, 1848

Eugene Louis Lami, Grand Staircase at Buckingham Palace State Ball, 1848

In going up the staircase, it is rigorously the custom to give precedence to those to whom you owe respect, and to yield to such persons the most convenient part of the stairs, which is that next the wall. Above all do not forget this last caution if you accompany a lady ; and a well-bred gentleman, at such a time, should offer his arm. When there are many ladies, he should bestow this mark of respect on the oldest. If you meet any one on the staircase, place yourself on the side opposite to the one he occupies. (Emily Thornwell, The lady's guide to perfect gentility, in manners, dress, and conversation. New York: Derby & Jackson, 1857. p. 85.)

Unless, of course, you don't. These ladies and gentlemen arriving for a ball at Buckingham Palace are not arranging themselves according to the rigorous custom described in the etiquette book. They seem much less organized, and just intent on waiting their turn to get in the ballroom.