The King’s despotic power, however, enabled him to make light of military discontent in time of peace. He resolved to keep up an army of 150,000 men, to drill it as it had never been drilled before, to educate the officers, to review all the troops every year, to build new fortresses, and to establish stores of money and munitions sufficient to enable Prussia to enter at a moment’s notice upon a war of eight campaigns. It is a highly significant fact that in Frederick’s secret estimates for the future struggle the annual contribution of Prussia was set down at 4,700,000 thalers and the sum to be extorted from Saxony at 5,000,000. The balance of the 12,000,000 thalers, which was the price of a campaign, must come from the royal accumulations. Frederick’s own expenses were only 220,000 thalers a year. At the close of his reign, when the total revenue of the State was not quite 22,000,000 thalers, the treasure amounted to more than 51,000,000, a sum fully five times as great as that which he had inherited from his father. Frederick was compelled by his past to stand to arms all his life through. With advancing years he became more lonely and more subject to disease. In 1765 he lost his sister, the Margravine of Schwedt, and next year the aged Madame de Camas, whom he always called Mamma. His old friends died one by one and the French wits had vanished. His brothers, Henry and Ferdinand, were often estranged from him by his bitter words. Yet to the end of his life he prided himself on his cheerfulness between the attacks of gout and he permitted no disease to interrupt his labours. These were devoted first, as we have seen, to making the land secure from attack by means of the army, and also to guarding it from famine by methods which may next be considered. Close on the heels of these essential duties came tasks of fresh development and reform, the acquisition of West-Preussen in 1772, and new endeavours to uphold Prussian prestige against the House of Hapsburg. It is of course impossible to calculate exactly the damage which a country suffers in time of war. Moral gains and losses count in the long run for more than material, and no statistics even of material losses are truly satisfactory. As between one Prussian province and another, however, a rough comparison may be made by means of the growth or decline of the population. Silesia and the lands east of the Oder had naturally suffered most, since, in addition to their quota of soldiers slain, they had long endured the presence of invading armies. In Silesia the numbers fell by 50,000, about one in twenty-three, but further north, in the districts in which the Russians had encamped, the proportion was nearly five times as heavy. Frederick’s own estimate was that one-ninth of his subjects had perished.