During the Gilded Age, dropping by a friend’s house was acceptable and encouraged, as long as it conformed to an extensive menu of rules and regulations. Calling cards were an essential element in this exercise with an additional set of requirements outlined in over twenty pages by Ward McAllister in his book Society As I Have Found It (1890). In short, upon arrival at the house, the card was presented to the head butler at the front door, forwarded to the lady of the house who would decide whether or not to receive you. Specific corners of the card would be folded down to indicate the lady’s wishes or her absence. More rules were to follow.
Selection of calling cards from NHS collection. Note the fold on the Astor card.