Those first rules of conduct laid down how meetings between officials ought to be organised, the Congress of Vienna of 1815 playing an important part. The international rules of protocol were then aligned to one another as much as possible. These rules of protocol still exist and are internationally identical.
Rules of etiquette involve conduct among people. Rules of etiquette are changing continuously, as society is changing, appropriating other norms and values to itself. For instance, years ago it was not becoming to eat in the streets; today this has changed completely.
Rules of protocol apply to officials who represent organisations. So protocol is much more business-like and supports certain business purposes. The principal aim of protocol is to organise meetings as smoothly as possible. Good examples are farewell receptions where applying the rules of protocol can prevent people from having to queue for hours to say their farewells.
In essence, protocol management has always been about optimising relationships by maximising personal attention and systemising logistics. Protocol management enables the staging of the personal encounter. In a world where personal attention has become scarce and technology a facilitator for rules and procedures, protocol management provides us with a unique vision in which personal time is the greatest good we can give to someone. It is the modern currency of relationships.