 The duke was probably of Gascon (Basque) lineage, though the "Vita Hludovici" calls him "of the race of Franks" ("ex gente Francorum").After subduing the Basques and receiving the submission of the duke Lupus in 768-769, Charlemagne devised in 778 a territorial re-organization intending to undermine the native order of Vasconia (Gascony) and Lupus II's authority by (re-)establishing counties.Seguin was appointed count in Bordeaux, possibly from a rival family of duke Lupus II.