De Roos (literally, "The Rose"), also locally known as Roosmolen or Koren op de Molen, is a wind and platform mill situated within the municipality of Delft, in the South Holland province of the Netherlands.
The mill was originally constructed on the southern city wall of Delft but was later relocated and rebuilt above the western fortifications of the Dutch municipality in 1679. Two principal phases of implementation of the Delft mill followed this reconstruction. The first was dated 1728, while the second was from the 1760s. The building has been the subject of multiple restoration projects, commencing in the late 1920s and concluding in 2023. The artistic work, whose historical background remains largely uncharted before its 1679 reconstruction, represents the sole surviving mill within the erstwhile fortified zone of Delft, among the eighteen that previously operated within the Dutch city.
On the current site of De Roos, at 111-112 Phoenixstraat, there originally stood a post mill called Gasthuismolen, which was destroyed during a storm in the second half of the 17th century. Previously bordered by the tramway and then the railway line connecting the city to The Hague, the site of De Roos mill has been situated above the Willem of Orange railway tunnel since the second half of the 2010s. The construction of this infrastructure necessitated the hydraulic jacking and the underpinning of the De Roos complex — mill, miller's house, warehouse — and preventive archaeological excavations that revealed remnants of the windmill dating from the late 17th century and early 18th century, as well as elements of the western portion of the medieval city wall of Delft.
Despite periods of inactivity, particularly during periods of restoration and repair, the mill remains operational. It has been managed by many millers, including those from the Kouwenhoven, van Rhijn, and De Vreede families.
On June 29, 1967, the Dutch Cultural Heritage Agency designated the De Roos grain mill, along with the miller's house and warehouse surrounding its skirt, as a national monument. The windmill is conical in shape and of the skirt and platform type. It is rather massive in scope and height, constructed of bricks and jointed stones. The mill is equipped with a rotating cap, and the milling work, which transforms grains of cereals into flour, is powered by a complex set of elements, mostly mechanical, motorized, and electric for a few. The house and warehouse, also constructed of masonry bricks, feature facades with gables.
Location and situation
De Roos is situated in the western portion of the historic center of Delft, a municipality in the province of South Holland. The mill is situated at 112 Phoenixstraat. The entire De Roos complex, comprising the house and warehouse, is located at 112 and 111 Phoenixstraat, midway along this urban thoroughfare. The Delft Wind Building is situated to the south of Dirklangenstraat and to the north of Dirklangendwarsstraat, which together form an intersection with Phoenixstraat. Additionally, situated along this same urban axis are an ancient fortification tower (the Bagijnetoren) and one of the buildings of the , which serves as the headquarters of the Delfland Water Board. Phoenixstraat is bordered by Wateringsevest, a former canal dug parallel to the Delft city wall and now filled in. For urban architecture researchers C. Steffen and D.J.M. van der Voordt, the presence of the mill, which they describe as a "pleasant" and "landmark" structure situated in the heart of Delft's town center, imbues the Dutch city with a distinctive charm.
On Phoenixstraat, situated between Dirklangendwarsstraat and Bagijnestraat, another mill, designated for oil production and known as the "Steckmolen" or "molen De Otter," was in operation until 1918. The De Otter mill was situated at a distance of 20 meters from De Roos.
The last remaining windmill in Delft, previously situated atop a bastion platform, is currently located above the Willem van Oranje tunnel on the railway line connecting the city to The Hague.
The mill, like six other buildings protected as national monuments in the municipality of Delft—namely, the Maria van Jesse church, the water tower, the fortification tower, the Prinsenhof, the Walloon church, and the Oude Kerk—is situated in an isopleth of altitude at an elevation of 6 meters below sea level. Furthermore, the Delft Windmill is constructed on a subsoil formed during the Pleistocene Epoch. This substrate is predominantly clayey in composition, with lesser proportions of sand and peat.
History
From the Late Middle Ages to the end of the Modern Era
The Gasthuismolen, the first windmill built on the site of 111-112 Phoenixstraat The earliest known reference to a windmill on the site of 111-112 Phoenixstraat is from 1352. This mill was subsequently known as Gasthuismolen (or Bordeelmolen).
The existence of this late medieval mill is substantiated by a fiscal act promulgated by the then Count of Holland, William V (Willem van Beieren), which details the transfer of the windmill to the inhabitants of Delft. In this administrative document, the Gathuismolen is referenced under the Middle Dutch term "Gasthuse molen."
The existence of the Gasthuismolen is also corroborated by a map dated 1561 and created by Jacob van Deventer. It is then mentioned in 1582 in the context of a grain mill, although it was used in the early 17th century to grind malt for brewing beer. It is also referenced in July 1595 during the creation of a Delft square bearing its name and in 1601 in a document written by its miller, Gerrit Stevensz, which describes the destruction of a portion of the city wall near the mill.
A tempest destroyed the building in 1675.
Former site of De Roos and transfer and reconstruction at 111-112 Phoenixstraat
De Roos was initially constructed on the remains of a bastioned fortification (this section of the urban wall was destroyed during the 17th century), situated on the current Zuiderstraat — a thoroughfare in the southern part of the historic center of Delft. Subsequently, the edifice was situated near a fortified tower, designated as Oosterijke toren. The location of the initial construction site is indicated on a map dated 1678 and engraved by the Dutch painter Johannes Verkolje and published by the writer Dirck van Bleyswijck. Near the aforementioned mill was the Rotterdamse Poort, a fortified gateway that opened onto the southern city wall. It seems reasonable to posit that De Roos exhibited a similar architectural style to that of the Gasthuismolen, namely that it was initially a post mill. This element is attested by a document dated 1629 in which an accident between its string and pivot is mentioned. Despite the paucity of evidence, it can be surmised that De Roos existed on the bastioned rondel of the Oosterijke toren by the second half of the 16th century.
In June 1679, at the behest of Cornelis van Nierop, then proprietor of the land, the De Roos mill was relocated to the site of the Gasthuismolen. The current location at 111-112 Phoenixstraat was selected due to its superior wind exposure. Subsequently, the transfer and reconstruction of the building were undertaken by civil engineer and miller Floris (or Fons) van Mierop. The windmill was constructed on the foundations of a rondel, which was located in the western section of the wall that encircled the city of Delft. The semi-circular fortification, whose remains were identified during preventive archaeological operations in the 2000s and 2010s, was constructed using bricks and stones from the 13th century that had been reused. Additionally, the archaeological investigation revealed the presence of a canal, which constituted a defensive ditch following the current Dirklangenstraat and a loop urban road with two successive intersections with Phoenixstraat. This canal was dated to the first quarter of the 14th century and measured approximately 3 meters in width. It is plausible that the De Roos was still functioning as a "post mill" during its reconstruction on the Phoenixstraat site, as any new stone mill construction would have required a special permit from the Delft authorities.
Second and third phases of mill construction in the late 18th and 18th centuries Van Mierop died in December 1679, before the conclusion of the reconstruction initiative.
The reconstruction work, which commenced in the late 1670s, continued apace. In November 1681, a masonry cap was placed under the hexagonal structure of the mill's skirt. Furthermore, due to the sails rotating at an insufficient height—which required a minimum elevation of at least eight feet (approximately two meters) above the ground—the municipal council determined that modifications to the mill were necessary to align with architectural standards. The structure was subsequently incorporated into a five-meter-high masonry, and a timber framework was incorporated to regulate the wheel's operation.
In 1728, a semi-circular dwelling constructed from volcanic tuff was erected close to the mill. Intended to serve as a residence for the miller, this structure was complemented by the addition of a warehouse, also crafted from volcanic tuff blocks, which constituted the final element of the windmill complex.
In the 1760s, the De Roos entered its third construction phase and assumed its definitive architectural form. In approximately 1760, the De Roos, which had previously been a post mill, transformed into a tower mill. Following extensive drainage operations, the foundations were entirely re-masoned. The mill's skirt was reconstructed, and the building was raised by six meters. In January 1766, Jan de Bruyn obtained permission to install a hexagonal wooden gallery around the stone skirt of the windmill.
Contemporary period
From the early 19th century to the purchase of De Roos in 1926
At the beginning of the nineteenth century, the circular base was replaced with a hexagonal masonry structure. This transformation is documented in an engraving by topographer Balthasar Jooss dated 1822.
In 1829, Pieter van Rijn, previously employed at the Niew Leven grain mill in Hazerswoude, became the proprietor of De Roos. From May 1847, a section of the , constructed in 1829, ran adjacent to the Delft mill. In 1874, Pieter van Rijn's son, Klaas van Rijhn, assumed the role of miller from his father.
In the early 20th century, during the 1920s, the electrification of connecting The Hague to Delft resulted in the railway track being relocated from Oude Delft to Phoenixstraat. As the mill was situated on the new route, van Rijhn assumed the responsibility of ensuring the preservation of the windmill from probable destruction. In 1922, a 25-horsepower gas engine was integrated into the mill's mechanical system.
Following the demise of Klaas van Rhijn on December 14, 1925, the Hollandsche Molen, an organization established in 1923 for the conservation of Dutch mills, purchased De Roos in 1926. This acquisition by a nonprofit entity once again averted the destruction of the mill.
Initial restoration work In 1928, the gas engine that powered the mill's mechanism was replaced by an electric motor. The Hollandsche Molen leased the windmill and its residential outbuilding to the De Vreede family that same year. They remained tenants of De Roos until 2009, with Koos de Vreede being the last family member to operate the mill.