Grand Duke of Yonderre

The Grand Duke of Yonderre (Burgoignesc: Grand Duc Yonderresc, Gothic: Yondersche Großherzog) is the head of state of the Most Serene Grand Duchy Yonderre and commander-in-chief of the Yonderian Defence Force. The Grand Duchy Yonderre was consolidated in the 15th century under Joanus de Martigueux during the Crusader Conquest of Joanusterre as a Grand County, with de Martigueux as Grand Count. This was ratified in 1494 with the Treaty for the guarantee of Joanus' Land. The title of Grand Duke was conferred on future rulers of Yonderre by Pope Gregory XIII in 1574 following lengthy negotiations. The Yonderian nobility and Grand Count Falco I Sentinelleau had wanted the nation raised to the status of a Kingdom but due to stipulations in the Treaty for the guarantee of Joanus' Land, Yonderre could not be made a Kingdom as it belonged to the Crown of the Holy Levantine Empire de jure, despite the treaty having made Yonderre de jure autonmous and de facto independent in 1494.

The Yonderian monarch is the Grand Duke. Yonderre is an elective Grand Duchy with elections held immediately following the death of the incumbent Grand Duke. The resultant election is the traditional vote between the nine Counts of Yonderre, one of which ultimately ascends to the status of Grand Duke. The vote typically follows a few days after the death of the incumbent Grand Duke, allowing for the nine Counts to gather in Collinebourg. The shortest transition period between Grand Dukes was that of Falco IV Sentinelleau ascending three days after the passing of Auguste III de Somua in 1820, while the longest interval was when Falco I Sentinelleau ascended two months and two days after the passing of Joanus II de Donne in 1564. The longest reigning Grand Duke was Joanus X de Martigueux, whose rule of 62 years and 7 days spanned the latter half of the Great Depression, the entirety of the Great War and much of the Occidental Cold War. The shortest reigning Grand Duke was Giles III de Donne whose rule of three months and a day earned him the monicker "the Brief".

The incumbent Grand Duke is Auguste IV de Somua who ascended after the passing of Giles V Sentinelleau on April 17th, 1992. Because of the elective nature of the monarchy, Yonderian regnal names follow a system of Christian name followed by numeral and then the respective house of the Grand Duke, meaning that Auguste IV de Somua is the fourth Auguste to be Grand Duke and that his house is House de Somua.