Eustorge

 The name Rigaud (Eustorge [I]’s possible third son) suggests a relationship with the early vicomtes de Polignac (see Chapter 13.A), maybe through the female line. 

-https://fmg.ac/Projects/MedLands/AUVERGNE.htm#GuyAuvergnedied989A

1. EUSTORGE [I], son of --- . According to Europäische Stammtafeln[88], he was the possible son of Arimannus but the basis for this speculation is not known.

m ARSENDE, daughter of ---. The priest "Gauraceus" donated property to Saint-Julien de Brioude for the souls of "Rotberti vicecomitis ac coniugis eius et patris eius Ostorgii et matris Arsendana" by charter dated to [915/33][89].

 Eustorge & his wife had [four] children: 

• a) ROBERT [I] (-after [941]). . . .. .. . . . . .
• b) [BERNARD (-after 20 Jan [911]). ... ... ... ]
• c) [RIGAUD [III] (-after 20 Jan [911]). ... ... ] m AVA, ... ...

The charters of Etienne [II] Bishop of Clermont refer to two sets of "avunculi mei". The charter dated Feb 962 refers to "[avunculus meus]…[Austorgius]" in two separate parts of the text. It is possible that these refer to two different individuals of the same name, although this is not without doubt. One possible interpretation is that one set of "avunculi" were paternal uncles and the other maternal. However, it seems unlikely that Bishop Etienne would have had uncles with the unusual name Eustorge on both sides of his family. Whatever the solution, both sets of uncles are shown here separately.

"Avunculi" group one:  ... ... . . . 

"Avunculi" group two: ... ... . . . 

PLZ source for dates (c.840-917)