One explanation for the meaning of Rouelbeau is hence that the lords of the castle had difficulties to sleep at nights because of the loud noise from the croaking frogs and therefore had their servants beat on the water with sticks.

[7][8] Scattered archaeological finds in the (former) marshes give evidence that there were already settlements during the Roman times some two millennia ago, despite - or because of - the swampy conditions.

[9] A picture, which the Swiss polymath Hans Conrad Escher von der Linth drew in 1785, says in its caption that the castle was built in the fifth century CE by Gundobad, King of the Burgundians.

[citation needed] The same goes for a thesis which was commonly accepted in the 19th century and claimed that Rouelbeau was Quadruvium, the royal residence of Gundobad's son Sigismund of Burgundy.

[4] The fortress, whose ruins can be seen today, was founded at the beginning of the 14th century in the context of the decades-long power-struggle between the lords of Faucigny and the House of Savoy for the rule over Geneva's countryside.

[11] Its strategic location secured access to the newly founded settlement of Hermance on the southeastern shore of Lake Geneva to the house of Faucigny.

[13] A detailed survey, which was prepared for the planned sale of some of the area of Dauphiné to the pope and has been kept in the Vatican Apostolic Archive ever since, mentions that in that year Rouelbeau was still made of wood.

[13] The construction of the stonework structure whose ruins remain today took place in subsequent years, probably under the leadership of the knight Nicod de Ferney.

In 1355, the troops of Amadeus, nicknamed the Green Count, conquered Rouelbeau Castle[11] and the area was integrated in the County of Savoy.

[11] From 1915 onwards the marshes of Rouelbeau were systematically drained by channeling the Seymaz in order to counter the rural depopulation in the area.

[19] Based on 3D-photography of the area, a miniature model of the ruins was made from bronze, which in addition to numerous info plates provides the visitors with an overview.

[19] The site was opened to the public again in September 2016 with a two-day festival which saw many participants performing medieval reenactments in costumes, including a group of women from Meinier who dressed up as "White Ladies".

Proponents of the legend argue that the ghost has been linked to the disappearance of people and deaths from unexplained causes,[11] and that Christmas Eve is her preferred timing.

[5] In a version from 1870, which was published in 1902, a certain Jean Bahut told the story that he went out to the castle ruins on Christmas Eve as a sixteen-year-old during the French occupation of Geneva at the beginning of the 19th century to shoot some wild animals for dinner with his widowed and impoverished mother.

While the White Lady rewarded his commitment to his mother with a treasure of gold and silver, she punished his wealthy and greedy relative one year later in a deadly way by tricking and locking him into the vaults.

The neighbouring municipality of Choulex still bears the name of the family, whose lineage Humbert as the first lord of the castle was from and which was first mentioned in a document almost nine hundred years ago as Cholay.

However, they warned against dealing a second beating as a coup de grace, since the tomcat would in that case only recover its full power to throw its victim into hell.

The saga may be seen in the context of a troubling incident from 1567: during that year, the brothers Claude and Jenon Dexert, who lived at the fringes of the swamp, were accused of witchcraft.