The Illustre Lieve Vrouwe Broederschap (ILVB) is a fraternity dating from 1318 in the Brabant city of ‘s-Hertogenbosch. Today, the ecumenical society consists of eighteen Catholic and eighteen Protestant members, all of whom occupy a prominent position in the Dutch society. The brotherhood “takes care of its centuries-old material and intangible cultural heritage, promotes the christian togetherness and the fraternal bond, and keeps an eye on developments and problems in modern times”. ‘Illustre’ means famous and relates to the Sweet Mother Mary. The society is located in the Zwanenbroedershuis in ‘s-Hertogenbosch. Cappella Pratensis is the proud fellow resident of the house.
The Zwanenbroedershuis is also a museum. The rich collection contains eleven religious choir books of the fraternity, mostly from the 16th century. Nine books contain a rich wealth of polyphonic music, and in addition there are two books with Gregorian (single-voiced) choral music.