Is it possible for the main early modern french kings (Charles VIII, Louis XII, or Francis I) to effectively hold their gains in Italy, especially Naples and Milan, without succumbing to their enemies?
If so, then which PoD is best for this? Charles VIII not dying early by hitting his head against a door? Francis I defeating Charles V at Pavia?
If such a victory happens, then what happens next?
Could we see an earlier rise of France as a power player in Europe?
Could this situation end up accelerating the drive towards italian unification in the long term?
Would France still have the need for an alliance with the ottomans? And, speaking of the ottomans, would Charles' weaker position favour them?
Kill Charles VIII ! Let's have the Louis, the Bad and the Good.
PoD : the Dauphin Charles died at 5 or 6 (1475). After a few tries, Louis XI understands he would not have another son. Even if he dislikes him, the Duke of Orléans is the legitimate heir. Better to leave him the stronger state in Christianhood. A good thing would be a reconciliatory marriage Burgundy-Orléans (Louis and Mary have only a five-year age gap), but it would probably fail for the same reasons as OTL : the Netherlands elites are afraid of french dominion. Fortunately, there is always a Savoy princess when you need one, this one a niece of both Louis XI and his wife : Louise (b. 1462). When Mary of Burgundy dies (1482 - or butterfly?), Louis XI sees an opportunity, as OTL Treaty of Arras, with the engagement of Margarita of Austria to Louis of Orléans and Louise of Savoy firstborn son, Charles of Valois. When Louis XI dies (1483), Louis XII, sure of his alliance with the Savoy and of his rights, would aim for his legitimate patrimony : the duchy of Milan. Sure, the Anjou rights on the throne of Naples have merged with the crown, but why bother going for the other end of the peninsula when you have the richest province of Christiandom (save for these pesky Netherlands) at arms' length. Of course, no need to settle things with Aragon (why bother ?) or Austria, so Artois, Franche-Comté, Roussillon and Cerdagne stay french. The Duke of Brittany needs some lessons in realpolitik, but his feeble attempts to safeguard his duchy independence meet an early stop as his own nobility deserts him. His eldest daughter is engaged to Louis's second son, but it is well understood she would not be duchess of Britanny. In 1485 or so, the Kingdom of France has more or less the frontiers of OTL 1678 ! Pope Innocent VIII needs a strongman to put pressure on Ferdinand of Naples, so the wedding offer of second-tier french princess and the duchy of Valentinois for his son Franceschetto by Louis is fully appreciated. Lorenzo de' Medici is isolated, his family bank close to collapse. At Milan, young Gian Galeazzo is under the thumb of his uncle Lodovico il Moro, while his mother (and aunt to the Queen of France) is locked away in a castle. Venice is tempted by some discrete offers of Lombardy fiefdoms. In 1486, F
uria Francese, Milan falls to the troops of the Franco-Savoyard Alliance. In 1487, Florence is also taken by the French and the Pope. Savoy gets Montferrato and a strip of Liguria, the Pope Sienna, the second-tiers lords become vassals (Genova and Modena to France, Ferrara to the Papacy, Mantova to Venice) and the King of France is Duke of Milan and perpetual podestà and rector magnificus of Florence.
How long will hold the precarious, four-way, equilibrium of Northern Italy ?