Peru and Bolivia form a confederation.

The Peru–Bolivian Confederation (or Confederacy) was a short-lived confederate state that existed in South America between 1836 and 1839, a loose union between the states of Peru and Bolivia. It was seen as threat by influential politicians in neighboring countries, and its support for Chilean and Argentine dissidents in exile caused Argentina and Chile to wage war separately against the confederation. The Confederation collapsed after being defeated by a combined Chilean and Peruvian dissident force in what is now known as the War of the Confederation.