Organ tuning and temperament are essential elements of the soundscape of an organ. It is commonly assumed today that organ temperament practice shifted away from the welldocumented standard of meantone temperament toward circulating temperaments (welltempered or equal) around 1700. Written records and evidence from extant instruments, however, strongly suggest that unmodified meantone temperament remained common practice in North German organs until the 1740s. Even advocates of the new temperament designs such as Andreas Werckmeister had to admit that organ builders did not follow their suggestions. There is no evidence that retunings resulted in well-tempered systems; only meantone and equal temperaments are mentioned in the sources for retunings. The reason for suggesting new temperament systems was the requirements of ensemble accompaniment. The simultaneous use of instruments tuned at different pitches (Chorton, Kammerton) required extensive transposition, a practice that, due to the development of major-minor tonality, became increasingly difficult if not impossible with organs tuned in meantone temperament. Modifications of this temperament were suggested and sometimes carried out, but were generally not successful. Re-tempering an existing organ was a time-consuming task: in a large organ it could take months of work even for an experienced builder. The circumstances under which the organs had to be tuned constituted an important impediment to the introduction of new temperaments. An analysis of payments to bellows-treaders as recorded in church account books shows that the organs of St. Marien, Lübeck, were not retuned during the tenures of Franz Tunder and Dieterich Buxtehude. Thus, some of their organ works could not have been played on the organs available to them during their lifetimes. At this time, however, playing from a score was not acceptable for a professional organist, who was expected to extemporize even complex contrapuntal music. Organ music seems to have been written down mainly for study purposes.