The first organ of the Church of St. Mary was built around 1641 by organ builder Johan Lorentz (born around 1580 in Saxony, he died in 1650 in Elsinore).
The organ was furnished with ManualWerk with 9 stops, a PositivWerk with 7 stops and PedalWerk with 8 stops. The organ was rebuilt 1661-63 by organ builder Hans Christoff Frietzsch (born around 1600 in Germany, he died in 1674 in Germany). The rebuilding took place during the years when composer Diderich Buxtehude worked as organist at St. Mary Church (1660-68).
The rebuild rebuilt organ was in use until 1854 when organ builder Marcussen & Son built a new organ with 21 stops behind the old organ cases.
In 1960 organ builder Th. Frobenius & Sons replaced the Marcussen organ with a neoclassical organ. This organ had 9 stops in Great organ, 7 stops in Chaire organ, 5 stops in an added Brustwerk and 9 stops in Pedal organ. This organ stood until 1st October 1995 when a substantial donation made it possible to build a completely new organ modelled in historical way after the original organ behind the old cases. The remodelled organ was taken into use for the first time in February 1998. With respect to technique and sound, the organ presents itself as a Danish organ from around 1650. The new organ was built by Marcussen & Son. The Dutch professor, Dr. Cornelius H. Edskes, Groningen, was artistic advisor on the organ project, and cathedral organist Kristian Olesen, Roskilde, acted as church council consultant.
Specifications for the organ in St. Mary Church, built in 1997 by Marcussen & S\F8n, 30 stops.
Principal 8 F., Gedact 8 F., Octava 4 F., RohrFl\F6it 4 F., Quinte 3 F., Octava 2 F., ZifFl\F6it 1 1/2 F., MiksTur 4 Fach, Trompete 8 F.
Gedact 8 F., Principal 4 F., Fl\F6it 4 F., Quinte 3 F., Octava 2 F., Sesquialter, Scharf 3 Fach, Krumbhorn 8 F.
Gedact 8 F., Fl\F6it 4 F., GemsHorn 2 F., Sedecima 1 F., Regal 8 F.
UnterSatz 16 F., Principal 8 F., Gedact 8 F., Octava 4 F., RauschPfeiffe 2 Fach (now 3 Fach), Posaun 16 F., Trompete 8 F., Trompete 4 F.
Compass: ManualWerk and BrustWerk CDEFGA-c3; R\FCckWerk CDE-c3; PedalWerk CDE-d1. The pedalboard includes the notes Cs and Ds wich are connected with the notes cs and ds.
Couplers: MW-RW, BW-MW, MW-PW, RW-PW.
Tremulant for RW; Tremulant for the whole organ. Zimbelstern.
Blocking valves: MW/BW; RW; PW.
3 wedge-bellows with step arrangement; the bellows work as magazine in connection with an electric blower.
The front pipes in R\FCckWerk (FGA-a1 in Principal 4 F.) are the only original pipes from the Lorentz-Frietzsch-organ.
Temperament: Unequael (without wolf). Pitch: a1 435 hz by 15 gr. celcius. Windpressure for the whole organ: 66,3 mm.
Voicing: Olav S. Oussoren.
Mecanical action and registration; sliderchests.