The choir ambulatory or (de-) ambulatory (from Latin ambulare = to go) is the name given to the component of a traditional church building in the Christian West , which is arranged around the choir as a continuation of the aisles over the transept arms (if available) . The gallery appears as a gallery running around the choir apse and the choir bays , mostly made of slender stilted arches (with ends that extend downwards) on pillars . Choir ambulances were especially popular with pilgrim churches, such as stops on the Way of St. James to Santiago de Compostela
Choir galleries usually had liturgical functions, in which they were used as a processional walk for the clergy and altar servers . In historical pilgrim churches they also served the processions of the pilgrims, who were often numerous in the Middle Ages, who entered one of the aisles, then around the choir and back out via the aisle opposite. Their way often led past numerous relics exhibited on altars in chapels , which they had come to worship. Last but not least, these contributed to the pilgrims' willingness to donate.
Choir ambulances are almost always to be found in a structural unit with a radial row (along the radius) of chapels , which are also known as chapel wreaths. The number of chapels varies and depends on the size of the choir head . They often keep more or less wide spaces between each other, in which the outer wall is visible piece by piece and in which mostly individual windows are left open. In other cases they collide directly with one another, such as in Cologne Cathedral .
The ambulatory was covered with the usual vaults when they were built .
In the Romanesque era it was initially the continuous barrel vault . The openings in the arcades of the choir, the chapels and possibly the windows in the spaces between the chapels were joined by short transverse barrels in a radial arrangement, the so-called stitch caps . These stitch caps intersect with the main vault of the gallery in parabolic ridges (example: Notre-Dame de Châtel-Montagne ).
Circumferential groin vaults can also be classified as Romanesque . The rectangular vaults opposite the choir bays are divided into isosceles triangles by diagonal ridges. The fields opposite the curve of the choir apse have polygonal outlines, with diagonal ridges with strongly distorted triangles. The vault fields are separated by parallel ridges, also by belt arches , but also not at all, as is the case with St-Étienne de Nevers or Notre-Dame-du-Port de Clermont-Ferrand .