Since René's lifetime, Valdostano and Piedmontese historians have remarked on his tremendous political influence in the Valle d’Aosta and beyond. In around 1560, an anonymous memorialist stressed the geostrategic importance of the Valle d’Aosta and René's great wealth and authority there. But he also questioned René's fidelity to the dynasty (based on his subjects’ refusal to pay wartime subsidies being raised by the valley for the Duke) and pointed to the dangers of a powerful foreign family – the Madruzzo – inheriting René's position through the inheritance of his daughter Isabelle. This would enable the Prince-Bishop of Trento to ‘build a good project in said valley, where he could reach an agreement as a confederate with the Swiss at little cost, since he is of the German nation’. Foreign diplomats likewise remarked on René's power within the Sabaudian lands, albeit on the wane by the early 1560s. This appreciation of René's influence within the valley and beyond was highlighted by Jean-Baptiste de Tillier, an eighteenth-century Valdostano historian, secretary of the valley estates, and fierce defender of the valley's autonomy. Although René played a surprisingly modest role in De Tillier's Historique de la Vallée d’Aoste (1742), the author did stress the number of important secular and ecclesiastical offices held by the Challant in the valley, their numerous fiefs and castles, and the fact that they had always held ‘a very high rank and the first place in the whole jurisdiction of this duchy’.