Frederick's ultimate success in the Seven Years' War came at a heavy financial cost to Prussia. Part of the burden was covered by the Anglo-Prussian Convention, in Frederick received from 1758 till 1762 an annual £670,000 in British subsidies. These subsidies ceased when Frederick allied with Peter III, partly because of the changed political situation and also because of Great Britain's decreasing willingness to pay the sums Frederick wanted. Frederick also financed the war by devaluing the Prussian coin five times; debased coins were produced with the help of Leipzig mintmasters, Veitel Heine Ephraim, Daniel Itzig and Moses Isaacs. He also debased the coinage of Saxony and Poland. This debasement of the currency helped Frederick cover over 20 percent of the cost of the war, but at the price of causing massive inflation and economic upheaval throughout the region. Saxony, which occupied by Prussia for most of the conflict, was also nearly destitute to support the war effort. While Prussia lost no territory, the population and army were severely depleted by constant combat and invasions by Austria, Russia and Sweden. The best of Frederick's officer corps were also killed in the conflict. Although Frederick managed to bring his army up to 190,000 men by the time the economy had largely recovered in 1772, which made it the third-largest army in Europe, almost none of the officers in this army were veterans of his generation and the King's attitude towards them was extremely harsh. In addition, the war also cost Frederick personally. Many of Frederick's closest friends and family members, including his sister Wilhelmine, his brother Augustus William and his mother, died during the war.