The Tractatus pacis toti Christianitati fiendae, or Treaty on the Establishment of Peace throughout Christendom, was the unsuccessful project of universal peace initiated by King George of Bohemia in the 15th century. For its realization, serious diplomatic negotiations took place among European states in the years 1462-1464. The project abandoned the mediaeval idea of a universal empire headed by the Emperor Frederick III and the Pope for the concept, up to that time unknown, of a permanent union of independent and equal European states. The plan of King George of Poděbrady was proposed in the form of a multilateral agreement; this differed from conventional international instruments of the Middle Ages, which in general remained bilateral. The Project in determining the contractual terms of this agreement would have bound together the parties at issue with similar rights and responsibilities for the achieving of common goals. All this gives reason to assert that the Treaty on the Establishment of Peace throughout Christendom was the first multilateral treaty to have been closest in design to modern ones.