In the fifteenth and sixteenth centuries organs of great beauty and variety of tone, and rich in external adornment (there is a legend of an organ with pipes of pure silver erected by Philip II, king of Spain, in the _Escorial_), were built throughout Europe, the Germans enjoying the greatest reputation as builders. In France (Amiens Cathedral, Church of St. Bernard of Comminges, Chartres Cathedral); in Italy (Basilica di San Petronio, Bologna; Orvieto Cathedral, Church of St. John Lateran); in Spain (cathedrals of Salamanca, Zaragoza, Tarragona, Barcelona), and in Germany (churches and minsters in Vienna, Erfurt, Brunswick, Strassburg, Salzburg, Bamberg, Nürnberg) are still to be found organs and cases which excite admiration. In England small organs were principally used in the churches during the fifteenth century, though toward its close and during the sixteenth larger organs were imported from the Continent. During the sixteenth century the _Rückpositiv_ (back positive), a small portable organ for liturgic ceremonies, located at the organist’s back and communicating with a keyboard in the principal organ by means of trackers running under his feet, was invented and used until well into the nineteenth century, especially in France. A curious feature of the sixteenth-century cathedral organ of Spain, and one which influenced Spanish religious composition, was the _partida_, or division. All the stops were divided into two groups, each one acting on half the keyboard, the stops on one side sounding in the treble half, those on the other in the bass. Thus a Spanish cathedral organ with 120 stops in reality controlled only 60 sets of pipes. Compositions for these organs were called _partidas_, one hand playing full organ with all the reeds, the other using only flue stops. The part written for full organ was always _glosada_, or rich in brilliant passage-work and ornamentation. Organ builders in the earlier days were usually monks and priests, as all creative cultural activity was then concentrated in the church and especially in the monasteries. During the fifteenth and sixteenth centuries the lay builder, in contrast to the ecclesiastic, makes his appearance.