how many world-systems in 1400 AD ?

I have an historical question that I meant to ask someone in the know for
some time. I understand that by one definition there has always been only
one world economy and one world system. But let's think of the hyphenated
definition a la California school of WS which leads to the identification of
multiple world-systems.(Not sure whether Wallerstein would count differently
from Chase-Dunn.) How many world-systems were there in 1400 AD ? (Bill Gates
should make it easier to ask the same question in terms of other calendars -
Chinese, Jewish, Islamic, but let's stay with AD.)

Here in Canada, there might have been at least 3 world-systems at that
time - one at the Pacific coast, one in the North (Inuit) and one between
the prairies and the Atlantic coast. Several more in North, Central and
South America. Australia was probably a world-system by itself. Add Europe,
Asia, Africa - the total number of world-systems (definition of California
school) could have been quite considerable. Is there an historical WS atlas?

I picked 1400 AD, because it was before Columbus etc and before the fall of
Constantinople to the Osmans, but after the Mongol invasions in Europe, and
before the "discovery" of most of Africa by Europeans.

Just curious. Any takers?
Thanks,
Gert