Two events occurred during Frederick's reign, one of which illustrated the declining power of the Roman Church, while the other, unnoticed in the confusion of civil war, was destined to be the chief weapon for the overthrow of the priestly power. The first of these was the fall of the Eastern Empire, when Sultan Mohammed II. conquered Constantinople in 1453. Although this catastrophe had been long foreseen, the news of it nevertheless created a powerful excitement throughout Europe. One-fourth of the zeal expended on any one of the Crusades would have saved Turkey to Christendom: the German Empire, alone, could have easily repelled the Ottoman invasion; but each petty ruler thought only of himself, and the Popes were solely interested in preventing the Reformation of the Church. The latter, now--especially Pius II. (Æneas Sylvius)--were very eager for a new Crusade for the recovery of Constantinople: there was much talk, but no action, and finally even the talk ceased. [Sidenote: 1440.] The other event was a simple invention, which is chiefly remarkable for not having been made long before. The great use of cards for gambling first led to the employment of wooden blocks, upon which the figures were cut and then printed in colors. Wood-engraving, of a rude kind, gradually came into use, and as early as the year 1420 Lawrence Coster, of Harlem, in Holland, produced entire books, each page of which was engraved upon a single block. But John Gutenberg, of Mayence, about the year 1436, originated the plan of casting movable types and setting them together to form words. His chief difficulty was in discovering a proper metal of which to cast them, and a kind of ink which would give a clear impression. Paper made of linen had already been in use, in Germany, for about a hundred and thirty years. Gutenberg was poor, and therefore took a man named Fust, who had considerable means, as his partner. They completed the first printing-press in 1440, but several more years elapsed before the invention achieved any result. There was a quarrel between the two; Gutenberg withdrew, and Fust took his own assistant, Peter Schoeffer, as partner in the former's place. Schoeffer discovered the right combination of metal for the types, as well as an excellent ink. In 1457 appeared the first printed book, a Latin psalter; in 1461 the Latin Bible, and two years afterwards a German Bible. These Bibles are masterpieces of the printer's art: they were sold at from thirty to sixty gold florins a copy, which was just one-tenth the cost of a written Bible at that time. The art was at first kept a profound secret, and the people supposed that the books were produced by magic, as they were multiplied so rapidly and sold so cheaply; but when Mayence was taken by Adolf of Nassau, in 1462, during one of the civil wars, the invention became known to the world, and printing-presses were soon established in Holland, Italy and England. [Sidenote: 1462. THE INVENTION OF PRINTING.]