Cossonay

Town Canton of Vaud · District: Morges · about 5'000 inhabitants as of 1 January 2026

Origin of the name Founding Historical timeline Population over time Must-see historical sites Remains Sources and references Nearby villages

Origin of the name Cossonay

Cossonay owes its oldest written mention to a document of 1096, where the place is designated in the Latin form Cochoniacum. Variants then multiply rapidly over the course of medieval documents: de Cossonay around 1142, Cosonai in 1164, then Cossonai in 1228, before the current form stabilises. These old attestations relate, according to the most generally accepted toponymic explanation, to a Gallo-Roman estate name formed on a Latin or Latinised personal name, Cossinus or Cossonus, to which is added the Celtic suffix of possession -acum (or -acus), extremely frequent in the toponymy of the Swiss Romand Plateau to designate the rural estate of an owner. The primary meaning would thus be « the estate of Cossinus » or « of Cossonus », a type of formation characteristic of the period when the Celtic populations of the region had adopted Latin names while partly retaining their own language and their own customs. The inhabitants of Cossonay are commonly designated by the nickname Traîne-Gourdins (one also, more rarely, encounters the name Traîneurs-de-Sabre). This nickname remains very much alive today, borne in particular by a popular foot race organised every year in the municipality and by a local sports club. Its precise origin, however, could not be established with certainty: none of the sources consulted explains why this particular nickname attached itself to the people of the town, so it is a traditional and affectionate name rather than an official demonym in the strict sense.

Founding of Cossonay

Cossonay is not a foundation planned for a precise date but a town born progressively around a fortified castle, on a promontory overlooking the Veyron valley. The site had already experienced much earlier occupation: remains of a Gallo-Roman villa and the course of a Roman road have been located in the area, and a necropolis of the early Middle Ages was brought to light there during excavations carried out in 1828. The very first written mention of the place, in 1096, concerns moreover a donation: the local lord, Uldric (sometimes Frenchified as Ulrich) of Cossonay, gives the church built on his allod to the Benedictine convent of Romainmôtier, which then establishes a priory there in the mid-12th century, subsequently dependent on the Benedictine priory of Lutry until the Reformation. The family of the lords of Cossonay, known from this period and linked to the powerful house of Grandson, builds around its castle a lordship that extends, at its height in the 13th and 14th centuries, over a vast territory stretching from La Chaux to Boussens and from Dizy to Gollion, with subsidiary possessions as far as Prangins, Nyon, L'Isle, Bercher or Surpierre. It is this dynasty that gives the nascent town its institutional framework: the status of a borough with franchises is granted to the inhabitants from the 13th century, a recognition sometimes dated more precisely to 1264 according to certain sources, and three fortified enclosures succeed one another between the 11th and 14th centuries to protect the settlement developing at the foot of the castle. Two members of the family even reach the episcopate of Lausanne, Jean de Cossonay from 1240 to 1273 then Aymon de Cossonay from 1355 to 1375, a sign of the regional weight acquired by the lineage. The birth of the town is thus due as much to the initiative of a seigneurial power as to the strategic position of the site, on a height commanding the passages between the foot of the Jura and the Plateau. It was only with the extinction of the family of Cossonay, at the very beginning of the 15th century, that power changed hands lastingly: the lordship then passed to the house of Savoy, which retained it, in the form of a châtellenie, until the Bernese conquest of 1536.

History of Cossonay

Roman period. A Gallo-Roman villa settles in the area, served by a Roman road whose course has been located; these remains attest to an occupation of the site well before the medieval town.

Early Middle Ages. A necropolis of the early Middle Ages, brought to light during excavations in 1828, attests to a continuous occupation of the site between the Roman period and the founding of the feudal town.

1096. First written mention of the place, in the Latin form Cochoniacum. The lord Uldric (or Ulrich) of Cossonay gives the church built on his allod to the Benedictine convent of Romainmôtier.

11th-12th century. The castle of Cossonay develops and becomes one of the most important in the region; Romainmôtier establishes a priory there around the middle of the 12th century, which will later fall under the Benedictine priory of Lutry until the Reformation.

around 1142-1228. The name of the place appears in several successive spellings in the charters: de Cossonay around 1142, Cosonai in 1164, Cossonai in 1228, before the current spelling stabilises.

1240-1273. Jean de Cossonay, son of lord Jean I, occupies the episcopal seat of Lausanne. Under his influence, the castle of Cossonay reaches its peak and ranks among the largest in the region.

13th century. The inhabitants of Cossonay obtain the status of burghers and benefit from franchises; some sources place the granting of borough rights more precisely around 1264, though this point could not be fully cross-checked with certainty.

11th-14th century. Three fortified enclosures succeed one another around the town, built respectively in the 11th, 13th and 14th centuries, as the settlement develops at the foot of the castle.

1355-1375. Aymon de Cossonay, canon then bishop of Lausanne, in turn occupies the episcopal seat; he dies in 1375.

around 1250-1260. The church of the town is remodelled: the Romanesque choir with three apses is replaced by a Gothic ante-choir with a rectangular Cistercian-type choir, and a basilical nave is raised.

around 1390. A major fire destroys a large part of the town, including its archives; the church itself is damaged and partially rebuilt in the aftermath.

14 April 1398. Jeanne de Cossonay, heiress of the lordship after the extinction of the direct male line, grants the inhabitants a new code of liberties, partly intended to facilitate reconstruction after the fire.

1407. The church's bell tower, still standing today, is built by Jean de Lilaz, a local priest referred to as « master of the bell tower ».

1414. The Count of Savoy confirms the franchises of the inhabitants of Cossonay.

after 1417. Death of Jeanne de Cossonay, last direct representative of the de Cossonay family; for lack of descendants, her succession is disputed among several claimants, including her own husband.

1406-1421. The house of Savoy appropriates the fief of Cossonay, taking advantage of the vacancy left by the extinction of the seigneurial line; the sources do not fully agree on the date to adopt for this shift, some mentioning mainly 1406 as the start of the succession crisis and others 1421 as the date of completion of Savoyard control, without it being possible to decide with certainty between the two.

from 1430. Cossonay sends representatives to the Estates of Vaud as a «bonne ville» (good town).

1475. During the Burgundian Wars, Bernese troops set fire to the town and the castle of Cossonay.

1536. The Bernese conquest of the Vaud country brings Cossonay under Bernese administration. The Protestant Reformation takes hold there and the church becomes a Reformed church; the fortifications are subsequently restored by Bern.

1550. The town has 111 hearths (households), according to a census of the time, which gives an idea of the size of the locality in the mid-16th century.

1664-1668. Construction of the building that will become the Auberge du Cerf, then used as the town house; its arcaded ground floor still exists today.

1693. Jean-Jacques Delessert (1643-1704), already châtelain of L'Isle and governor of Cossonay, buys the castle of Cossonay from the estate of the de Penthaz family. The estate will remain in the hands of his family for nearly two centuries.

1712. The west façade of the church of Cossonay is rebuilt.

1756-1779. Construction of the Cure (parsonage), based on plans by the architect Gabriel Delagrange.

18th century. The medieval castle, remodelled several times since the Middle Ages, is rebuilt largely in the outline of its present form. One source attributes this building work to a certain Benjamin de Lessert, information that could not be cross-checked with a second independent source and which even poses a chronological problem, since the best-known Benjamin Delessert of this banking family was born in 1773; it could be an earlier namesake within the same family, but this point remains to be verified.

1798. With the end of the seigneurial regime and the creation of the canton of Léman then, from 1803, of the canton of Vaud, Cossonay becomes the chief town of the new district of Cossonay, an administrative status it will retain for more than two centuries.

1803. The priory of Cossonay, deconsecrated from its religious function since the Reformation, is converted into a district prison; it will keep this function until 1970.

1815-1816. New doors and windows are opened up in the church of Cossonay.

1826-1831. Construction of the present-day town hall, in a neoclassical style, based on plans by the architect Jean-Siméon Descombes.

1855. The railway line reaches the region; a station is inaugurated under the name of Penthalaz-Cossonay station.

1879. The castle of Cossonay leaves the estate of the Delessert family, which had owned it since 1693.

1892-1897. An initiative committee is formed in 1891 to link the old town, up on the height, with the railway station, down below. The Compagnie du chemin de fer funiculaire de Cossonay is founded on 30 August 1892, and the funicular makes its first regular run on 28 August 1897, with two wooden carriages using water counterweights.

1900. The church of Cossonay is listed as a Vaud historic monument.

1913. The station, until then called Penthalaz-Cossonay, is renamed Cossonay station, because of the administrative status of district chief town that the municipality then holds.

1970. The prison housed in the former priory closes; the building is then converted to other uses, in particular residential.

1982. The funicular of Cossonay switches from hydraulic to electric traction: last run with the old system on 22 February, resumption of service on 18 June of the same year.

1995. The church of Cossonay is listed as a Swiss cultural property of national importance.

2000. The district court of Cossonay is transferred to Nyon, a development that comes shortly before the complete disappearance of the district.

31 August 2006. The district of Cossonay is dissolved as part of the territorial reorganisation of the canton of Vaud. As early as the next day, 1 September 2006, Cossonay and the majority of the municipalities of the former district (including La Chaux, Cottens, L'Isle and Montricher) join the new district of Morges; about ten other municipalities of the former district move to the new district of Gros-de-Vaud.

2007-2014. The loss of chief-town status by Cossonay revives a dispute with the neighbouring municipality of Penthalaz, on whose territory the station is physically located, over the name of the station. The Federal Office of Transport recommends in May 2012 the name Cossonay-Penthalaz station, a recommendation approved by the Federal Council on 17 March 2014 and effective from the timetable of 14 December 2014.

2012-2014. The funicular of Cossonay undergoes a complete renovation, with new rolling stock in the colours of the regional company.

2020-2021. The funicular closes temporarily for works aimed at increasing its capacity, the line then carrying around 330,000 passengers per year.

2021. The federal census puts the population of Cossonay at 3608 inhabitants. The available sources do not fully agree on the exact pace of demographic growth at the turn of the 2020s, with some statistical publications giving, for neighbouring years, significantly higher figures; this is a period of rapid growth and the various estimates do not all seem to refer exactly to the same reference date.

2026. Cossonay remains, twenty years after the disappearance of its district, an independent municipality of the district of Morges, with strong demographic growth, with no merger with a neighbouring municipality recorded in the sources consulted.

Population of Cossonay

507

1764

702

1798

938

1850

1'060

1900

1'108

1910

1'214

1950

1'529

1970

1'553

1980

2'043

1990

2'558

2000

3'315

2010

3'608

2021

4'942

2025

5'018

2026

Historic sites in Cossonay

The Priory. Founded at the end of the 11th century by the convent of Romainmôtier, to which lord Uldric of Cossonay had given the church of the place, the priory long constituted the religious heart of the town. Deconsecrated after the Reformation, the building served as a district prison from 1803 to 1970, before being converted into housing. Its history alone sums up the town's major stages: medieval ecclesiastical foundation, a shift towards administrative and judicial use under the Vaud regime, then contemporary reconversion.

The church (former church of Saint-Pierre-et-Saint-Paul). The present-day building, first mentioned in 1096 under the patronage of Saints Peter and Paul, succeeds two older constructions, one from the 8th century and the other from the 9th. Its Romanesque choir with three apses was replaced, around 1250-1260, by a Gothic ante-choir with a rectangular Cistercian-type choir, while a basilical nave was raised at the same time. Damaged by the fire at the end of the 14th century, it was then partially rebuilt, before receiving in 1407 its present bell tower, the work of the priest Jean de Lilaz. Having become a Protestant church after the Bernese conquest and the Reformation, it underwent further transformations, including a new west façade in 1712 and new openings in 1815-1816. It is today listed as a Vaud historic monument since 1900 and registered as a Swiss cultural property of national importance since 1995.

The Château de Cossonay (Château Delessert). Built on a promontory overlooking the town, the castle was the seat of the powerful family of the lords of Cossonay, for whom it became one of the most important fortresses in the region in the 13th century. Transformed and remodelled several times over the centuries, after having served as the seat of the lordship and then the châtellenie of Cossonay under Savoy and then under Bern, it was rebuilt largely in the outline of its present form in the 18th century. The Genevan and later Vaud family of the Delesserts owned it from 1693, the date of its acquisition by Jean-Jacques Delessert, until 1879.

L'Auberge du Cerf. Built between 1664 and 1668 to serve as the town house, this building with an arcaded ground floor was later converted into an inn. It today houses a restaurant awarded two stars in the Michelin guide, run for more than thirty years by chef Carlo Crisci, making it one of the few places in the town that directly link its architectural past to contemporary gastronomic recognition.

The Town Hall. Built between 1826 and 1831 in a neoclassical style by the architect Jean-Siméon Descombes, the Town Hall long housed the authorities of the district chief town, then those of the municipality, and remains today the seat of the municipal administration.

The old town and its ramparts. The historic heart of Cossonay preserves the layout of the fortified medieval settlement, protected by three successive enclosures built in the 11th, 13th and 14th centuries. The narrow streets and rows of buildings of the old town, today perched above the more recent station district, still fairly well convey the silhouette of the town as it developed around its castle.

Le funiculaire de Cossonay. Put into service on 28 August 1897 to link the old town, up on the height, with the railway station, down below, this funicular originally operated with water counterweights before switching to electric traction in 1982. Renovated between 2012 and 2014 and then temporarily closed in 2020-2021 for capacity works, it remains in service today and carries several hundred thousand passengers a year, making it one of the historic facilities most used daily by residents.

Remains in Cossonay

Gallo-Roman remains. Archaeological excavations have brought to light remains of a Gallo-Roman villa on the territory of Cossonay, as well as the course of a Roman road that crossed the area. These discoveries attest to an occupation of the site several centuries before the first written mention of the medieval town, without it being possible to establish a direct link between this ancient settlement and the establishment of the feudal castle.

Necropolis of the early Middle Ages. A necropolis dating from the early Middle Ages was discovered during excavations in 1828. It attests to a continuous occupation of the site between the end of the Roman period and the establishment of the medieval lordship, even though the sources consulted give no more precise details on the extent of the excavations or the number of burials brought to light, a point that would deserve to be cross-checked with specialised archaeological publications.

Remains of the former medieval fortress. The original medieval fortress, seat of the powerful lords of Cossonay and one of the largest castles in the region at its height in the 13th century, has today almost entirely disappeared in its original form: the building visible today, generally called the Château Delessert, results mainly from an 18th-century reconstruction. The oldest states of the medieval construction are now known only through archaeological excavations and through the mentions made of them in old texts.

Traces of the three fortified enclosures. The layout of the three successive enclosures that protected the town between the 11th and 14th centuries remains partly legible in the plan of today's old town, even though the walls themselves now survive only in fragments, integrated into more recent buildings.

Sources

Other villages near Cossonay

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