Complex sentence: It is certain that Robert Giguère was in New France in 1651, however, according to George-Emile Giguère and others, in 1644, he was missing from French census records.
Split into simpler sentences: It is certain that Robert Giguère was in New France in 1651. However, according to George-Emile Giguère and others, in 1644, he was missing from French census records.