 Complete the following phrase:  In 1756, Frederick attempted to forestall Britains ficing of a Russian army on Prussias border by negotiating an alliance with England at the Convention of Westminster, in which Prussia would protect Hanover against French attack and England would no longer subsidise Russia. This treaty triggered the Diplomatic Revolution in which Habsburg Austria and Bourbon France, who had been traditional enemies, allied together with Russia to defeat the Anglo-Prussian coalition. To strengthen his strategic position against this coalition,on 29 August 1756, Fredericks well-prepared army preemptively invaded Saxony. His invasion triggered the Third Silesian War and the larger Seven Years War, both of which lasted until 1763. Frederick quickly captured Dresden, besieged the trapped Saxon army in 