
What Prussia? In 16th century?
Speaking about really useful allies for 16th century France-Ottomans and Zapolya, maybe Jagiellons too (weaker Habsburgs and lack of Pavia could encourage Sigismund to fully support his brother-in-law or to claim Bohemia for himself) I wonder how situation in Hungary develop? Seems that Zapolya should be more successful.
Right. Here the OTL rise of Prussia is almost ASB...
Well Jan everything depend by how we arrive to this Habsburg England-Burgundy, Habsburg Empire and not-Habsburg Spain.
In my opinion the smarter way for doing it is:
a) Maximilian has children (at least a son and a daughter by Bianca Maria) but is not really needed (as we have another way for having the same outcome)
b) Isabella Juana (aka Juan and Margaret’s daughter) and/or Miguel da Paz (Manuel and Isabella’s son) survive. Either would be enough but is better if both survive as their wedding would be the most logical thing to do (and we would have the least butterflies)
c) Karl, Duke of Burgundy married an ATL daughter of Catherine of Aragon, who is her only living child and the heiress of England (we have three ways for it: a posthumous daughter by Arthur; the only surviving child she had by a longer living Arthur; a daughter by Henry born early from their wedding, who without the Spanish takeover by Philip, will happen in 1505).
Poland here will be most likely allied with Austria as he will most likely marry Maximilian and Bianca’s daughter instead of Barbara Zapolya.
Take out Ernest and Eleanor (ATL children of Maximilian and Bianca) and you can have the same results with the OTL children of Philip and Juana
1) Eleanor, Queen of Poland as second wife of Sigismund I (no need for a match with either England or Portugal)
2) Karl V, Holy Roman Emperor, Duke of Burgundy and King of England jure uxoris (married to his cousin Elizabeth Tudor, daughter and heiress of Henry VIII of England and named after both her grandmothers)
3) Isabella, likely still Queen of Denmark
4) Maximilian, Archduke of Austria and husband of Anne of Hungary and Bohemia
5) Mary, Queen of Hungary as wife of Louis II
6) Catherine
Karl will not like much the need to marry two sisters to the Jagiellons and to renounce to his share of Austria in favor of Maximilian but is still better than marrying Anna himself (plus Austria will be only a bother for him as part of Burgundy is in the Holy Roman Empire and so his branch can still be the Imperial one and England fully replace it)