Say Felipe II dies of some disease or other a couple years before
Carlos abdicated OTL. Does he leave the whole undivided empire to his
brother Ferdinand? Decide to retain his position till his death (and
leave it to whom?) Given the size of the Habsburg inheritance and the
complexity of it's governance, it's hard to see it not being divided
at some point in the 16th century. Of course, if we assume a division
between possible heirs of Ferdinand when he kicks the bucket in the
1560's, the split might not have gone as OTL...
Bruce