A. Bongioanni notes that this surname derives from a given name that evokes baptism with the water of the Jordan and the memory of a pilgrimage to the Holy Land. In the Chansons de geste, forms such as Jerusalan and Jerusalant are documented. From that name, according to Olivieri, would derive the Veneto and Friuli-Venezia Giulia surnames Rosalén, Rosolén and Rosolán, to which perhaps the Piedmontese Orsolano should be added.

E. De Stefani provides more precise information on the geographical distribution. The full form Gerusalemme is documented from the mid-16th century in Priuso, a frazione of Socchieve, in the mountainous zone of northern Friuli-Venezia Giulia known as Carnia, where the surname became extinct around the mid-19th century. The aphetic variants Rusalem and Rusalen, arisen from the fall of the initial syllable Hier-/Geru-, are still current in Travesio and in Caneva di Sacile, in the Pordenone area.

De Stefani explains that the motivation of the name is double: it was attributed to pilgrims who had travelled to the Holy Land, or else to children of parents who wished to express their Christian faith through a biblical name. In that context, he notes that in the 13th century the order of the Cavalieri dell'Ospedale di Gerusalemme operated in the canale di Socchieve, an institutional presence that could have reinforced the use of the name in the zone. As kindred surnames of the same etymon in Veneto he mentions Orsalemo and Rosolèn, documented in Gaiarine, in the Treviso area.