The construction dates from the end of the 9th to the beginning of the 10th Century.
The primitive chapel that constitutes the ancient part of the building takes the place of our crypt days of the past. It can be found under the ground of the actual church. It has remained buried under the remains of successive buildings over the centuries, however, fortunately traces of it were discovered during renovation work between 1964/7.
St Léger was the patron saint of the church of Basse-Nendaz.