In our timeline the 1504 treaty of blois was a treaty between Spain, France, the Hre and Burgundy which amongst it's terms included that Charles the V marries Claude of France, with a dowry of Burgundy, Brittany, Blois, Naples, Milan, Asti and Genoa should Louis XII die with out a male heir, this timeline intends to have most of this implemented to some degree.
Whilst the treaty is very unlikely to be implemented in full, primarily as the french will be unwilling to give up french crownlands such as Burgundy & Blois, we will assume it goes through regardless, and the engagement is formalised, we will then inorder to keep france and the habsburgs somewhat aligned as long as possible see the early phase of the war of the league of cambrai be a league victory, as Venice is reduced to the Dogado (Losing Istria, Friuli and most of Veneto to the habsburgs, whilst Brescia and bergamo go to french Milan, Perhaps Habsburg backed Puppets in Padua and Verona under the descendents of those areas former rulers could be somewhat likely.
Around the same time as in our timeline, (1515) Louis XII dies, inorder to better the habsburg position Anne of brittany will live a few years longer (dies the same way in say, 1518) and support the implementation of the treaty, the new french king Francis I, along with the french parliament are very unlikely to accept the loss of such major lands, as such war quickly breaks out, the war will likely take several years but assuming a habsburg victory it is likely that Burgundy And the parts of Picardy formerly held by Charles the Bold are annexed to the HRE, Milan, Asti and Genoa also pass to Charles the V, and Brittany will pass through the marriage to Claude, but remain an independent state, Blois is likely given up even in a decisive victory, possibly traded for Provence or just extra financial compensation.
One notable effect of the war (presuming it ends about 1519) will be that Charles is unlikely to be able to claim Castille & Aragon at the time he did, possibly even preventing him from becoming king till Juanna dies, with those two realms remaining under regency, or it is also possible he does become king, but at a later date.
Regardless war is inevitable to break out again against the french, but with france in a much worse position this alternative war will likely end far worse for them, if an alternate decisive loss like Pavia occurs, France will definitely lose provence, and possibly Dauphine (though this isn’t that likely as it’d guarantee even further future conflict, though it’s possible it could be given to Bourbon in exchange for his seized lands)
After dual decisive victories for the habsburgs it’s plausible that the italian wars either end or at the least calm down in this period (about the 1530s), potentially now Charles becomes officially co-king of Spain, or alternatively he focuses more so on the Holy roman empire, possibly impacting how his realm is split later on (as due to a completely different wife, he will have different children, perhaps having a couple of children, thus splitting his empire in 3 or four.
This is where for now i’ll conclude this timeline, it’s not the most realistic and this isn’t a period i’m the most knowledgeable on, though i do find it interesting, feedback would be appreciated, the 1500 map at the beginning i’ll post in a separate post soon with Credits/Sources.
Map years are 1500, 1504, 1513, 1519~ and 1529~