In the eighteenth century, a special genre of instrumental ensemble playing developed in church music: works were written for a wind instrument and obbligato organ. The geographical center of this genre was the kingdom of Saxony along with Thuringia. The majority of these works specify oboe as the wind instrument, less frequently horn or even trumpet, flute, or bassoon. Besides a few compositions in a free style, these were predominantly chorale preludes in which the wind instrument played the cantus firmus (the chorale melody), and the organ, usually in trio textures, performed elaborate, often very virtuoso figurations.