A representation of the document recording the meeting between Bishop Hatto and Andreas and Rodolfus on the Septimer Pass in the year 913.
On 2nd May 1769 Baron Zurlauben presented a dissertation to the Académie Royale des Inscriptions et des Belles-Lettres in Paris.
In June that year, Peter, 3rd Count de Salis, recorded: “M. de Marschlins, amongst many other documents which regard our family, has found one very ancient and very particular, this is a receipt of Archbishop Hatto of about the middle of the tenth century, wherein he says that he was met upon the Mountain of Sett. (i.e. Septimer) by the noble Andrew and Rodolph of Castellaz in the valley of Bregalia, Posessores terrarum Salicarum, with their dependants; The sum, or quit rent, which he received of them was not very considerable; but from this document some pretend that our name may find its derivation. M. de Zurlauben has made a dissertation upon it and presented it to the Academy of Sciences, where it has been acknowledged as one of the oldest documents any Gentleman’s family can, or has been able to produce.”
It is perhaps no coincidence that, also in 1769, M. Marschlins, with M. Seevis de Salis, asked Peter for a copy of the Patent of Count of the Empire conferred upon his grandfather, as they wished to include it amongst other documents to be presented at Versailles, in order for them to obtain the “Entrée du Roi“. Peter refused to allow this, but the dissertation is likely to have been prepared to assist this purpose.
Baron Zurlauben, a Swiss patriot who had served the French Crown with distinction during the war of the Austrian Succession, was also a tireless and talented historian, a member of the Académie des Inscriptions et Belles-Lettres and a prolific writer. One of his long-standing projects (never fully completed), was to create a genealogical work documenting the Swiss nobility. He had been collecting evidence to support this for many years  and his extensive research about the meeting between Archbishop Hatto and the Salis brothers in 913 was part of this project.
In his dissertation, Baron Zurlauben considered the legal, historical, chronological and geographical circumstances surrounding the ancient document in astounding detail, demonstrating how the timing of the meeting on Mount Septimer would have coincided with Hatto’s tenure as Archbishop and his expedition into Italy to collect feudal dues on behalf of Emperor Conrad I.
Even before the dissertation was written, the contemporary historian, Johann Jacob Mascou (who died in 1761) had expressed concern about the validity of the document. Later historians have been no less dubious, but perhaps they did not have the opportunity to read the full dissertation, which is now published here for the first time. Father Nicolaus von Salis-Soglio gave short shrift to the hypothesis, and Professor Jean Rodolphe von Salis began his “Brief Historical Survey of the Salis Family” firmly in the thirteenth century. However, the story of the meeting of Andreas and Rodolph with Archbishop Hatto has fascinated generations of Salis, especially and William and his brother Henry Jerome who, in 1891, erected a tower at Castellatz to commemorate the meeting in 913 and 1,000 years of Salis history.
Click on the link below to view the report summarising Baron Zurlauben’s dissertation to the Académie Royale des Inscriptions et des Belles-Lettres. 
To view a transcript of Baron Zurlauben’s dissertation, click on the links below:
In 1891, William and Henry De Salis re-built the tower at Caslac (above Castasegna) - to commemorate that the Salis family has flourished in the Val Bregaglia for 1,000 years – and at least since the meeting with Bishop Hatto in 913.
 Rachel De Salis, De Salis Family English Branch (Henley-on-Thames, 1934), pp 109-10.
 Ursula Pia Jauch, Beat Fidel Zurlauben, 1720-1799, Söldnergeneral & Büchernarr (Neue Zürcher Zeitung, Zürich, 1999).
 P. Nicolaus von Salis-Soglio, Die Familie von Salis (Lindau i.B., 1891), p. 4.
 Professor Jean Rodolphe von Salis, Introduction to the Personenbestand (1953).
 “Sur un Titre Original de 913” in Histoire de L’ Académie Royale des Inscriptions et des Belles-Lettres (Paris, 1774), xxxvi, pp 166-75.