The Treaty of Versailles (also known as the First Treaty of Versailles) was a diplomatic agreement between Austria and France signed on 1 May 1756 at the Palace of Versailles in which the two countries offered each other mutual assistance if attacked by other powers, which was broadly interpreted as meaning Britain or Prussia. The Treaty established the Franco-Austrian Alliance which was to last in some form or another for the next thirty years. Within months of the agreement France and Austria found themselves engaged in the Seven Years War against the Anglo-Prussian Alliance which was to last until 1763. Along with the Westminster Convention the Treaty formed part of the Diplomatic Revolution which re-aligned the alliance systems of the major powers of Europe in the run-up to the war.