Butlers at the finest homes used to deliver them on a silver tray to their lords and ladies who would pronounce on their merits with a sniffy nod or a curt kiss-off. The calling card was, by societal whim, the only way past the transom for chancers seeking “face time” when it still meant that.

It was a simple notice of intention, status and credentials, a must-have accessory for everyone from the travelling salesman to the shopworn private detective — think of Raymond Chandler’s PI Philip Marlowe “calling on four million dollars” at the Sternwood mansion.