In 1807 France tried to force Portugal to join the Continental System, a commercial embargo against Britain. When the Portuguese Prince Regent, John refused to join, Napoleon sent General Junot to invade Portugal in 1807, resulting in the six Year Peninsular War. After Austria was defeated in 1805, the nation spent three years reforming its army. Encouraged by the events in Spain, Austria sought another confrontation with France to avenge their defeats and regain lost territory and power. Austria lacked allies in central Europe. Austria and Prussia requested that Britain fund their military campaigns and requested a British military expedition to Germany. Austria received £250,000 in silver, with a further £1 million promised for future expenses. Britain promised an expedition to the low countries and to renew their campaign in Spain. After Prussia decided against war, the Fifth Coalition formally consisted of Austria, Britain, Portugal, Spain, Sicily and Sardinia, though Austria was the majority of the fighting effort. Russia remained neutral even though they were allied to France.