lBy the 16th century the seven original calpulli had expanded from kinship groups to become residential groupings including neighbors, allies, and dependents.
lThe calpulli performed
vital local functions in distributing
land and labor and maintaining temples
and schools.
lDuring wars they
organized military units.
lCalpulli were governed by
councils of family heads, but
all families were not equal.
lDuring Aztec expansion a class of nobility (pipiltin) had emerged from privileged families in the most distinguished calpulli.