Furthermore, indulgences were made available for souls already in purgatory. This kind of indulgence seems to have been granted for the first time in 1476. It had long been been that the prayers of the living availed to shorten the pains of the departed, and the institution of masses for the dead was of long standing; but it was not without some difficulty that the Popes succeeded in establishing their claim to power over purgatory. Their power over the souls of the living was not disputed. The "Power of the Keys" had been given to Peter and transmitted to his successors; the "Treasury of the Church," [22] i. e., the merits of Christ and of the Saints, was believed to be at their disposal, and it was this treasury which they employed in the granting of indulgences;[23] but it seemed reasonable to suppose that their jurisdiction ended with death. Accordingly, Pope Sixtus IV, in 1477, declared that the power of the Pope over purgatory, while genuine, was exercised only per modum sufiragii, "by way of intercession." [24] The distinction was thought dogmatically important, but to the layman, who looked more to results than to methods, the difference between intercession and jurisdiction was trifling. To him the important thing was that the Pope, whether by jurisdiction or intercession, was able to release the soul of a departed Christian from the penalties of purgatory. It is needless to say that these indulgences for the dead were eagerly purchased. In filial love and natural affection the indulgence vendor had powerful allies.