Universal Postal Union replaced pairwise postal treaties with one shared standard

By the mid-1800s, international mail moved through a maze of separate bilateral treaties: any two countries that wanted to exchange letters directly had to negotiate their own terms — postal rates, handling rules, who paid what — and a letter traveling between two countries with no direct treaty between them had to be re-routed through an intermediate country under yet another, separately negotiated set of terms.

Heinrich von Stephan, a German postal official, had been developing the idea of a single international postal union for over a decade by the time he found real traction — the concept itself predated the eventual 1874 conference, but it took his direct advocacy, including meeting personally with Swiss federal councillor Eugène Borel ahead of the event, to move from proposal to an actual gathering of nations.

Replaced pairwise treaties with one shared standard—uniform charges, guaranteed transit, mutual recognition—so joining meant one treaty, not one per member.

Each border crossing previously required satisfying a separate treaty, multiplying complexity.

A single agreement set uniform charges and transit rights, so one set of rules covered all routes.

New members joined by signing one treaty instead of negotiating with every existing member.

The cost of adding a country stopped growing with network size, enabling rapid expansion.

When network value depends on pairwise coordination, replace many bilateral deals with one shared standard.

A letter posted in any member country could now travel to any other member country under one shared set of rules, without needing a separate bilateral treaty to cover its route, and any new country wanting to join the system only had to sign the one existing agreement rather than negotiate individually with every member already in it. Membership grew fast enough that the organization's name changed from the General Postal Union to the Universal Postal Union within four years.