aistians? ........do you mean aestii .........they are modern estonians, east-baltic people
venedae , logicically they can only be initially west-baltic people who first became germanized and later became slavitized ......then by the early middle-ages, the term was used by the lithuanians.
In the middle ages, the commonwealth of Poland-Lithuanian led to the poles claiming the term....ah..the monarchies, you have to have a greedy mind...it s mine, mine I say.
the "ae" at the end of the word indicates a mixed group ( ethnicity) of people, like samatae, bastanae, etc etc
hmmm
that -ae in end might mean something
lets see
ending in -οι -oi
sometimes means group of sons, ancestors,
sons of Keltos are Keltoi
sons of Makedon are Makednoi
ending in -es
sometimes means group of habitats dwellers allies
Crete people are Κρητες
but there is no special ocasion rule,
for example Italians are Italoi
the case of -ae might be connected with Greek -αι
that means a female name of tribe or City name
Female nouns in plural get -αι but we find no description of nation or tribe with -αι -ae in Greek
but we find city names like
Μυκηναι Mucenae
Αθηναι Athenae
that maybe means a territorial name, or a city name
I agree that ending in -ae describes plural with different form, probably a union, an alliance or a major toponymic description,
example Mycenae was a city, but we also consider as Mycenae that era Sparta Pylos etc
probably what Greek used as -ες, sarmatae - Σαυροματες.