▁f used ▁with ▁L ich ar re ▁in ▁ 1 8 4 1 ▁to ▁form ▁" Ma ul éon - L ich ar re ", ▁but ▁today ▁is ▁often ▁known ▁as ▁" Ma ul éon - S ou le ". ▁Histor ically , ▁Sou le ▁is ▁the ▁smallest ▁province ▁of ▁the ▁Bas que ▁Country ▁( 7 8 5   km 2 .). ▁Its ▁population ▁has ▁been ▁decre asing ▁( 2 3 , 8 0 3 ▁in ▁ 1 9 0 1 ; ▁ 1 6 , 0 0 6 ▁in ▁ 1 9 9 0 ; ▁ 1 5 , 5 3 5 ▁in ▁ 1 9 9 9 ). ▁ ▁Et ym ology ▁▁ ▁The ▁territory ▁is ▁named ▁X iber oa ▁in ▁Sou letin ▁Bas que , ▁Z ub ero a ▁in ▁standard ▁Bas que , ▁S ola ▁in ▁Gas con ▁and ▁Sou le ▁in ▁French ; ▁all ▁of ▁them ▁deriv ate ▁from ▁Sub ola , ▁previous ▁name ▁of ▁the ▁region ▁att ested ▁for ▁the ▁first ▁time ▁in ▁the ▁year ▁ 6 3 5 ▁in ▁the ▁di aries ▁of ▁a ▁Franco - B urg und ian ▁expedition ▁led ▁by ▁Duke ▁Ar ne bert ▁against ▁the ▁Bas ques . ▁Sub ola ▁comes ▁from ▁the ▁name ▁the ▁Rom ans ▁gave ▁to ▁the ▁Aqu it ani ▁tribe ▁that ▁inhab ited ▁the ▁region ▁by ▁the ▁time ▁of ▁their ▁arrival , ▁the ▁Sub ur ates , ▁also ▁called ▁S ibus ates ▁by ▁Julius ▁Ca esar ▁in ▁his ▁Comment ari i ▁de ▁B ello ▁Gall ico ▁and ▁Sy