A history of Lanthony Abbey records that “Hugo de Laci” had “nepos...miles” who, after a long military career, eventually became a Templar (“sub habitu Templariorum...”). Assuming that “nepos” in the source quoted above can be interpreted as nephew, one parent of Hugh’s “nepos” the Templar was Hugh’s sibling. The description of this person in the source follows a sentence recording Hugh’s brother Walter, but the two sentences are not linked. 1
Gilbert de Lacy is probably the unnamed “nepos” of [his uncle] Hugh de Lacy.