Since they were both minors at the time, their uncle Count John of Freiburg-Neuchâtel took up government as their guardian.

The districts of Badenweiler, Rötteln and Hachberg-Sausenberg then formed an almost contiguous area Markgräflerland, north of Basel and south of Freiburg.

Count John of Freiburg-Neuchâtel and his wife Marie of Chalon had six children, but they all died in childhood.

After John's death (19 February 1458), Rudolf inherited further possessions in the Free County of Burgundy.

In 1451 and 1452, Rudolf accompanied King Frederick III on his journey to Rome for his coronation.