Third, the Brethren, in all their schools, made regular use of hymn-books; and the scholar learnt to sing by singing hymns. Sometimes the hymns were in a separate volume; sometimes a selection was bound up with the Catechism. But in either case the grand result was the same. As we follow the later fortunes of the Brethren we shall find ourselves face to face with a difficult problem. How was it, we ask, that in later years, when their little Church was crushed to powder, these Brethren held the faith for a hundred years? How was it that the "Hidden Seed" had such vitality? How was it that, though forbidden by law, they held the fort till the times of revival came? For answer we turn to their Catechism. They had learned it first in their own homes; they had learned it later at school; they had made it the very marrow of their life; they taught it in turn to their children; and thus in the darkest hours of trial they handed on the torch of faith from one generation to another. We come now to another secret of their strength. Of all the Protestants in Europe the Bohemian Brethren were the first to publish a Hymn-book; and by this time they had published ten editions. The first three were in Bohemian, and were edited by Luke of Prague, 1501, 1505, 1519; the fourth in German, edited by Michael Weiss, 1531; the fifth in Bohemian, edited by John Horn, 1541; the sixth in German, edited by John Horn, 1544; the seventh in Polish, edited by George Israel, 1554; the eighth in Bohemian, edited by John Blahoslaw, 1561; the ninth in German, 1566; the tenth in Polish, 1569. As they wished here to appeal to all classes, they published hymns both ancient and modern, and tunes both grave and gay. Among the hymn-writers were John Hus, Rockycana, Luke of Prague, Augusta, and Martin Luther; and among the tunes were Gregorian Chants and popular rondels of the day. The hymns and tunes were published in one volume. The chief purpose of the hymns was clear religious instruction. The Brethren had nothing to conceal. They had no mysterious secret doctrines; and no mysterious secret practices. They published their hymn-books, not for themselves only, but for all the people in the country, and for Evangelical Christians in other lands. "It has been our chief aim," they said, "to let everyone fully and clearly understand what our views are with regard to the articles of the Christian faith." And here the hymns were powerful preachers of the faith. They spread the Brethren's creed in all directions. They were clear, orderly, systematic, and Scriptural; and thus they were sung in the family circle, by bands of young men in the Brethren's Houses, by shepherds watching their flocks by night, by sturdy peasants as they trudged to market. And then, on Sunday, in an age when congregational singing was as yet but little known, the Brethren made the rafters ring with the sound of united praise. "Your churches," wrote the learned Esrom Rüdinger, "surpass all others in singing.