It would be hard to determine whether the Great or the Positive is the older division of the pipe organ, since they both have their roots in antiquity. The various national ancestors of the Great (Blockwerk, Grand-Orgue, Hauptwerk, Hoofdwerk, Organo Grande, etc.) represented different tonal schemes, goals and periods, but in many ways they were similar, since they contained the basic foundation stops of the organ, and functioned as the center of its design.
The Blockwerk was the earliest representation of this concept, and by the 15th century it had reached a size which is astounding: some containing more than 30 ranks of principals, but without a stop action. Hardly duplicated in modern times, a modest blockwerk of 17 ranks of principals from 1480 would have pipes pitched at 16,8,8,8,5 1/3,5 1/3,4,4,4,22/3,22/3,22/3,2,2,2,11/3,11/3.
After the invention of stop action, the Great (I will use this generic term for it and all its ancestors) grew to a maturity and breadth of design in the 16th and 17th centuries using all four families of tone (principals, flutes, reeds and strings). A generic stoplist from that age might read: 16,16,8,8,8,4,4,22/3,2,V,VI, V,16,8,8. This is a design which combines both vertical (8-4-2) and horizontal (8-8-8) tonal elements. In the 18th and 19th centuries, variations in size and outlook occurred, but the Great still remained the home for the major principal chorus and the tonal center of the organ. Some have suggested that the Great became too large in the 19th century, but there were many instruments with 40-rank Greats during and before the time of Bach. In fact, there was a general decline in the size of the Great compared to the overall size of the organ during this time, as other divisions rose to prominence.
One of the most difficult aspects in studying the Great and its history is the difference in national styles, along with the changes within each national style over the centuries. If the Great can be thought of as originating in the low countries and spreading throughout Europe from there, it seemed to acquire a new life of its own in each new location. In Germany, the low countries and France, large, tonally mature instruments were common from the early 17th century. In France, the Grand-Orgue achieved monumental size compared to the other divisions. In northern Europe, other divisions were nearly equal in size to the Great. In Italy and Spain, the Organo Grande was large compared to the other divisions, and many instruments had only one manual. Southern European voicing was lighter than in northern areas, and many of the higher pitched principals were available separately, rather than being bound up in mixtures.
In England, the overall size of the organ remained small, compared to continental instruments, until the middle of the 19th century and, likewise, the Great remained small compared to developments just across the channel. Fortunately, even though organs were small, the principal chorus on the Great remained complete, so that integrity and musicality were intact, but on a reduced scale.
In the United States, organs followed European influences, but with interesting variations to suit church needs in the new land. In New England, the instruments followed the ideas of the small English organs, while further west, German builders created their own versions of the small central-European instruments. A modest principal chorus was the norm for the Great on these early American instruments, and it was not until the 19th century that large-scale Greats with fully developed choruses appeared.
By the early 20th century, the Great had lost much of its upperwork and chorus reeds. The tonal design was becoming more horizontal with each succeeding decade, as flutes and strings took the place of the vertical principal chorus. By 1910, it was not unusual to find a Great of
8,8,8,8,8,8,4- and the 4' was a soft flute!
With the revival of vertical tonal design in the 1930s, upperwork returned to the Great, but it was a long. slow process for builders to rediscover how to scale and voice mixtures to achieve the sounds so long lost in the instrument. Even tough the upperwork returned to the Great, the reeds were often ignored, and even the largest organs built between 1930 and 1950 might be without them. It is curious to see a stoplist from this era with perhaps 30 or more ranks on the Great, and not a single reed.
With the academic interest in the organ in the 1960s and the organ reform movement under way, a different slant to the design of the Great developed. Rejecting horizontal elements in tonal design, the Great became almost purely vertical, and a stoplist of 8,4,2,11/3,IV,8 would represent some thinking during this time. Such rejection of the balanced Great of the 17th century was disappointing. and builders soon realized that a combination of horizontal and vertical concepts was necessary to return musicality to the instrument.
Today, there are as many different approaches to designing the Great as there are builders, and nearly every period and national concept has been rediscovered and tried. But within this diversity, the Great still maintains its position as the foundation of the organ, and the division from which all else in the organ is derived or centered upon.